Advanced Elec. Installations: Inspection, Testing and Commissioning

The construction industry

An electrician working for an electrical contracting company works as a part of the broader construction industry. This is a multi-million-pound industry carrying out all types of building work, from basic housing to hotels, factories, schools, shops, offices and airports.

The construction industry is one of the USA’s biggest employers, and carries out contracts to the value of about 10% of the USA's gross national product.

Although a major employer, the construction industry is also very fragmented. Firms vary widely in size, from the local builder employing two or three people to the big national companies employing thousands.

Of the total workforce of the construction industry, 92% are employed in small firms of less than 25 people.

The yearly turnover of the construction industry is about $65 billion. Of this total sum, about 60% is spent on new building projects and the remaining 40% on maintenance, renovation or restoration of mostly housing.

In all these various construction projects the electro-technical industries play an important role, supplying essential electrical services to meet the needs of those who will use the completed building.

The building team

The construction of a new building is a complex process which requires a team of professionals working together to produce the desired results. We can call this team of professionals -- the building team, and their interrelationship.

The client is the person or group of people with the actual need for the building, such as a new house, office or factory. The client is responsible for financing all the work and , therefore, in effect, employs the entire building team.

The architect is the client's agent and is considered to be the leader of the building team. The architect must interpret the client's requirements and produce working drawings. During the building process the architect will supervise all aspects of the work until the building is handed over to the client.

The quantity surveyor measures the quantities of labor and material necessary to complete the building work from drawings supplied by the architect.

Specialist engineers advise the architect during the design stage. They will prepare drawings and calculations on specialist areas of work.

The clerk of works is the architect's 'on-site' representative. He or she will make sure that the contractors carry out the work in accordance with the drawings and other contract documents. They can also agree general matters directly with the building contractor as the architect's representative.

The local authority will ensure that the proposed building conforms to the relevant planning and building legislation.

The health and safety inspectors will ensure that the government's legislation concerning health and safety is fully implemented by the building contractor.

The building contractor will enter into a contract with the client to carry out the construction work in accordance with contract documents. The building contractor is the main contractor and he or she, in turn, may engage subcontractors to carry out specialist services such as electrical installation, mechanical services, plastering and painting.

Ill. 1 The building team.

The electrical team

The electrical contractor is the subcontractor responsible for the installation of electrical equipment within the building. An electrical contracting firm is made up of a group of individuals with varying duties and responsibilities. There is often no clear distinction between the duties of the individuals, and the responsibilities carried by an employee will vary from one employer to another. If the firm is to be successful, the individuals must work together to meet the requirements of their customers. Good customer relationships are important for the success of the firm and the continuing employment of the employee.

The customer or his representatives will probably see more of the electrician and the electrical trainee than the managing director of the firm and , therefore, the image presented by them is very important. They should always be polite and seen to capable and in command of the situation. This gives a customer confidence in the firm's ability to meet his or her needs.

The electrician and his trainee should be appropriately dressed for the job in hand, which probably means an overall of some kind. Footwear is also important, but sometimes a difficult consideration for a journeyman electrician. E.g., if working in a factory, the safety regulations may insist that protective footwear be worn, but rubber boots may be most appropriate for a building site. However, neither of these would be the most suitable footwear for an electrician fixing a new light fitting in the home of the managing director! The electrical installation in a building is often carried out alongside other trades. It makes sound sense to help other trades where possible and to develop good working relationships with other employees.

The employer has the responsibility of finding sufficient work for his employees, paying government taxes and meeting the requirements. The rates of pay and conditions for electricians and trainees are determined by negotiation, which will also represent their members in any disputes. Electricians are usually paid at a rate agreed for their grade as an electrician, approved electrician or technician electrician; movements through the grades are determined by a combination of academic achievement and practical experience.

The electrical team will consist of a group of professionals and their interrelationship can be expressed as shown in Ill. 2.

Designing an electrical installation

The designer of an electrical installation must ensure that the design meets the requirements of the NEC/NEMA Wiring Regulations for electrical installations and any other regulations which may be relevant to a particular installation. The designer may be a professional technician or engineer whose job it's to design electrical installations for a large contracting firm. In a smaller firm, the designer may also be the electrician who will carry out the installation to the customer's requirements. The designer of any electrical installation is the person who interprets the electrical requirements of the customer within the regulations, identifies the appropriate types of installation, the most suitable methods of protection and control and the size of cables to be used.

A large electrical installation may require many meetings with the customer and his professional representatives in order to identify a specification of what is required. The designer can then identify the general characteristics of the electrical installation and its compatibility with other services and equipment, as indicated in the Regulations. The protection and safety of the installation, and of those who will use it, must be considered, with due regard to the Regulations. An assessment of the frequency and quality of the maintenance to be expected will give an indication of the type of installation which is most appropriate.

The size and quantity of all the materials, cables, control equipment and accessories can then be determined. This is called a 'bill of quantities'.

It is common practice to ask a number of electrical contractors to tender or submit a price for work specified by the bill of quantities. The contractor must cost all the materials, assess the labor cost required to install the materials and add on profit and overhead costs in order to arrive at a final estimate for the work. The contractor tendering the lowest cost is usually, but not always, awarded the contract.

To complete the contract in the specified time the electrical contractor must use the management skills required by any business to ensure that men and materials are on site as and when they are required. If alterations or modifications are made to the electrical installation as the work proceeds which are outside the original specification, then a variation order must be issued so that the electrical contractor can be paid for the additional work.

The specification for the chosen wiring system will be largely determined by the building construction and the activities to be carried out in the completed building.

An industrial building, for example, will require an electrical installation which incorporates flexibility and mechanical protection. This can be achieved by a conduit, tray or trunking installation.

In a block of purpose-built flats, all the electrical connections must be accessible from one flat without intruding upon the surrounding flats. A loop-in conduit system, in which the only connections are at the light switch and outlet positions, would meet this requirement.

For a domestic electrical installation an appropriate lighting scheme and multiple socket outlets for the connection of domestic appliances, all at a reasonable cost, are important factors which can usually be met by a PVC insulated and sheathed wiring system.

The final choice of a wiring system must rest with those designing the installation and those ordering the work, but whatever system is employed, good workmanship is essential for compliance with the regulations. The necessary skills can be acquired by an electrical trainee who has the correct attitude and dedication to his craft.

Ill. 2 The electrical team.

Legal contracts

Before work commences, some form of legal contract should be agreed between the two parties, that's , those providing the work (e.g. the subcontracting electrical company) and those asking for the work to be carried out (e.g. the main building company).

A contract is a formal document which sets out the terms of agreement between the two parties. A standard form of building contract typically contains four sections:

1 The articles of agreement - this names the parties, the proposed building and the date of the contract period.

2 The contractual conditions - this states the rights and obligations of the parties concerned, e.g. whether there will be interim payments for work completed, or a penalty if work is not completed on time.

3 The appendix - this contains details of costings, e.g. the rate to be paid for extras as daywork, who will be responsible for defects, how much of the contract tender will be retained upon completion and for how long.

4 The supplementary agreement - this allows the electrical contractor to recoup any value-added tax paid on materials at interim periods.

In signing the contract, the electrical contractor has agreed to carry out the work to the appropriate standards in the time stated and for the agreed cost. The other party, say the main building contractor, is agreeing to pay the price stated for that work upon completion of the installation.

If a dispute arises the contract provides written evidence of what was agreed and will form the basis for a solution.

For smaller electrical jobs, a verbal contract may be agreed, but if a dispute arises there is no written evidence of what was agreed and it then becomes a matter of one person's word against another's.

Management systems

Smaller electrical contracting firms will know where their employees are working and what they are doing from day to day because of the level of personal con tact between the employer, employee and customer.

As a firm expands and becomes engaged on larger contracts, it becomes less likely that there is anyone in the firm with a complete knowledge of the firm's operations, and there arises an urgent need for sensible management and planning skills so that men and materials are on site when they are required and a healthy profit margin is maintained.

When the electrical contractor is told that he has been successful in tendering for a particular contract he is committed to carrying out the necessary work within the contract period. He must therefore consider:

++ by what date the job must be finished;

++ when the job must be started if the completion date is not to be delayed;

++ how many men will be required to complete the contract;

++ when certain materials will need to be ordered;

++ when the supply authorities must be notified that a supply will be required;

++ if it's necessary to obtain authorization from a statutory body for any work to commence.

In thinking ahead and planning the best method of completing the contract, the individual activities or jobs must be identified and consideration given to how the various jobs are interrelated. To help in this process a number of management techniques are available. In this Section we will consider only two: bar charts and network analysis. The very preparation of a bar chart or network analysis forces the contractor to think deeply, carefully and logically about the particular contract, and it's therefore a very useful aid to the successful completion of the work.

BAR CHARTS

There are many different types of bar chart used by industry, but the object of any bar chart is to establish the sequence and timing of the various activities involved in the contract as a whole. They are a visual aid in the process of communication. In order to be useful they must be clearly understood by the people involved in the management of a contract. The chart is constructed on a rectangular basis, as shown in Ill. 3.

All the individual jobs or activities which make up the contract are identified and listed separately down the vertical axis on the left-hand side, and time flows from left to right along the horizontal axis. The unit of time can be chosen to suit the length of the particular contract, but for most practical purposes either days or weeks are used.

The simple bar chart shown in Ill. 3(a) shows a particular activity A which is estimated to last 2 days, while activity B lasts 8 days. Activity C lasts 4 days and should be started on day 3. The remaining activities can be interpreted in the same way.

With the aid of colors, codes, symbols and a little imagination, much additional information can be included on this basic chart. E.g., the actual work completed can be indicated by shading above the activity line as shown in Ill. 3(b) with a vertical line indicating the number of contract days completed; the activities which are on time, ahead of or behind time can easily be identified. Activity B in Ill. 3(b) is 2 days behind schedule, while activity D is 2 days ahead of schedule. All other activities are on time. Some activities must be completed before others can start. E.g., all conduit work must be completely erected before the cables are drawn in.

This is shown in Ill. 3(b) by activities J and K. The short vertical line between the two activities indicates that activity J must be completed before K can commence.

Useful and informative as the bar chart is, there is one aspect of the contract which it can't display. It can't indicate clearly the interdependence of the various activities upon each other, and it's unable to identify those activities which must strictly adhere to the time schedule if the overall contract is to be completed on time, and those activities in which some

flexibility is acceptable. To overcome this limitation, in professionals developed the critical path net work diagram which we will now consider.

NETWORK ANALYSIS

In large or complex contracts there are a large number of separate jobs or activities to be performed. Some can be completed at the same time, while others can not be started until others are completed. A network diagram can be used to co-ordinate all the interrelated activities of the most complex project in such a way that all sequential relationships between the various activities, and the restraints imposed by one job on another, are allowed for. It also provides a method of calculating the time required to complete an individual activity and will identify those activities which are the key to meeting the completion date, called the critical path. Before considering the method of constructing a network diagram, let us define some of the terms and conventions we shall be using.

Critical path

This is the path taken from the start event to the end event which takes the longest time. This path denotes the time required for completion of the whole contract.

Float time

Float time, slack time or time in hand is the time remaining to complete the contract after completion of a particular activity.

Float time _ Critical path time _ Activity time

The total float time for any activity is the total lee way available for all activities in the particular path of activities in which it appears. If the float time is used up by one of the early activities in the path, there will be no float left for the remaining activities and they will become critical.

Activities

Activities are represented by an arrow, the tail of which indicates the commencement, and the head the completion of the activity. The length and direction of the arrows have no significance: they are not vectors or phasors. Activities require time, manpower and facilities. They lead up to or emerge from events.

Dummy activities

Dummy activities are represented by an arrow with a dashed line. They signify a logical link only, require no time and denote no specific action or work.

Event

An event is a point in time, a milestone or stage in the contract when the preceding activities are finished.

Each activity begins and ends in an event. An event has no time duration and is represented by a circle which sometimes includes an identifying number or letter.

Time may be recorded to a horizontal scale or shown on the activity arrows. E.g., the activity from event A to B takes 9 hours in the network diagram shown in Ill. 4.

Ill. 4 A network diagram for Example 1.

EX1

Identify the three possible paths from the start event A to the finish event F for the contract shown by the network diagram in Ill. 4. Identify the critical path and the float time in each path.

The three possible paths are:

1 event A-B-D-F 2 event A-C-D-F 3 event A-C-E-F.

The times taken to complete these activities are:

1 path A-B-D-F_9_8_7_24 hours 2 path A-C-D-F_4_12_7_23 hours 3 path A-C-E-F_4_5_6_15 hours.

The longest time from the start event to the finish event is 24 hours, and therefore the critical path is A-B-D-F.

The float time is given by:

Float time_Critical path_Activity time

For path 1, A-B-D-F, Float time_24 hours_24 hours_0 hours

There can be no float time in any of the activities which form a part of the critical path since a delay on any of these activities would delay completion of the contract. On the other two paths some delay could occur without affecting the overall contract time.

For path 2, A-C-D-F, Float time_24 hours_23 hours_1 hour

For path 3, A-C-E-F, Float time_24 hours_15 hours_9 hours

EX2

Identify the time taken to complete each activity in the network diagram shown in Ill. 5. Identify the three possible paths from the start event A to the final event G and state which path is the critical path.

The time taken to complete each activity using the horizontal scale is:

activity A-B_2 days activity A-C_3 days activity A-D_5 days activity B-E_5 days activity C-F_5 days activity E-G_3 days activity D-G_0 days activity F-G _0 days Activities D-G and F-G are dummy activities which take no time to complete but indicate a logical link only. This means that in this case once the activities preceding events D and F have been completed, the contract will not be held up by work associated with these particular paths and they will progress naturally to the finish event.

The three possible paths are:

1 A-B-E-G 2 A-D-G 3 A-C-F-G.

The times taken to complete the activities in each of the three paths are: path 1, A-B-E-G_2_5_3_10 days path 2, A-D-G_5_0_5 days path 3, A-C-F-G_3_5_0_8 days.

The critical path is path 1, A-B-E-G.

Ill. 5 A network diagram for Example 2.

Constructing a network

The first step in constructing a network diagram is to identify and draw up a list of all the individual jobs, or activities, which require time for their completion and which must be completed to advance the contract from start to completion.

The next step is to build up the arrow network showing schematically the precise relationship of the various activities between the start and end event. The designer of the network must ask these questions:

1. Which activities must be completed before others can commence? These activities are then drawn in a similar way to a series circuit but with event circles instead of resistor symbols.

2. Which activities can proceed at the same time? These can be drawn in a similar way to parallel circuits but with event circles instead of resistor symbols.

Commencing with the start event at the left-hand side of a sheet of paper, the arrows representing the various activities are built up step by step until the final event is reached. A number of attempts may be necessary to achieve a well-balanced and symmetrical network diagram showing the best possible flow of work and information, but this time is well spent when it produces a diagram which can be easily understood by those involved in the management of the particular contract.

EX3

A particular electrical contract is made up of activities A to F as described below:

A_an activity taking 2 weeks commencing in week 1 B_an activity taking 3 weeks commencing in week 1 C_an activity taking 3 weeks commencing in week 4 D_an activity taking 4 weeks commencing in week 7 E_an activity taking 6 weeks commencing in week 3 F _an activity taking 4 weeks commencing in week 1.

Certain constraints are placed on some activities because of the avail ability of men and materials and because some work must be completed before other work can commence as follows:

Activity C can only commence when B is completed.

Activity D can only commence when C is completed.

Activity E can only commence when A is completed.

Activity F does not restrict any other activity.

(a) Produce a simple bar chart to display the activities of this particular contract.

(b) Produce a network diagram of the program and describe each event.

(c) Identify the critical path and the total contract time.

(d) State the maximum delay which would be possible on activity E without delaying the completion of the contract.

(e) State the float time in activity F.

Ill. 6 (a) Bar chart and (b) network diagram for Example 3.

(a) A simple bar chart for this contract is shown in Ill. 6(a).

(b) The network diagram is shown in Ill. 6(b). The events may be described as follows:

Event 1_the commencement of the contract.

Event 2_the completion of activity A and the commencement of activity E.

Event 3_the completion of activity B and the commencement of activity C.

Event 4_the completion of activity F.

Event 5_the completion of activity E.

Event 6_the completion of activity C.

Event 7_the completion of activity D and the whole contract.

(c) There are three possible paths:

1 via events 1-2-5-7 2 via events 1-4-7 3 via events 1-3-6-7.

The time taken for each path is:

path 1_2 weeks_6 weeks_8 weeks path 2_4 weeks_4 weeks path 3_3 weeks_3 weeks_4 weeks_10 weeks.

The critical path is therefore path 3, via events 1-3-6-7, and the total contract time is 10 weeks.

(d) We have that Float time_Critical path time _Activity time Activity E is on path 1 via events 1-2-5-7 having a total activity time of 8 weeks.

Float time_10 weeks_8 weeks_2 weeks.

Activity E could be delayed for a maximum of 2 weeks without delaying the completion date of the whole contract.

(e) Activity F is on path 2 via events 1-4-7 having a total activity time of 4 weeks.

Float time_10 weeks_4 weeks_6 weeks.

On-site communications

Good communication is about transferring information from one person to another. Electricians and other professionals in the construction trades communicate with each other and the general public by means of drawings, sketches and symbols in addition to what we say and do.

DRAWINGS AND DIAGRAMS

Many different types of electrical drawing and diagram can be identified: layout, schematic, block, wiring and circuit diagrams. The type of diagram to be used in any particular application is the one which most clearly communicates the desired information.

Layout drawings

These are scale drawings based upon the architect's site plan of the building and show the positions of the electrical equipment which is to be installed.

The electrical equipment is identified by a graphical symbol.

The standard symbols used by the electrical contracting industry are those recommended by the Standard, Graphical Symbols for Electrical Power, Telecommunications and Electronic Diagrams. Some of the more common electrical installation symbols are given in Ill. 7.

A layout drawing is shown in Ill. 8 of a small domestic extension. It can be seen that the mains intake position, probably a consumer's unit, is situated in the store room which also contains one light controlled by a switch at the door. The bathroom contains one lighting point controlled by a one-way switch at the door. The kitchen has two doors and a switch is installed at each door to control the fluorescent luminaire. There are also three double sockets situated around the kitchen. The sitting room has a two-way switch at each door controlling the centre lighting point. Two wall lights with built in switches are to be wired, one at each side of the window. Two double sockets and one switched socket are also to be installed in the sitting room. The bedroom has two lighting points controlled independently by two one-way switches at the door.

The wiring diagrams and installation procedures for all these circuits can be found our guide Basic Electrical Installation Work.

As-fitted drawings

When the installation is completed a set of drawings should be produced which indicate the final positions of all the electrical equipment. As the building and electrical installation progresses, it's sometimes necessary to modify the positions of equipment indicated on the layout drawing because, for example, the position of a doorway has been changed. The layout drawings indicate the original intentions for the positions of equipment, while the 'as-fitted' drawing indicates the actual positions of equipment upon completion of the job.

Detail drawings

These are additional drawings produced by the architect to clarify some point of detail. E.g., a drawing might be produced to give a fuller description of the suspended ceiling arrangements.

Ill. 7 Installation symbols.

Schematic diagrams

A schematic diagram is a diagram in outline of, for example, a motor starter circuit. It uses graphical symbols to indicate the interrelationship of the electrical elements in a circuit. These help us to understand the working operation of the circuit.

An electrical schematic diagram looks very like a circuit diagram. A mechanical schematic diagram gives a more complex description of the individual elements in the system, indicating, for example, acceleration, velocity, position, force sensing and viscous damping.

Ill. 8 Layout drawing for electrical installation.

Ill. 9 Block diagram showing the layout of a high-volume voltage discharge lighting circuit.

Ill. 10 Wiring diagram of two-way switch control.

Block diagrams

A block diagram is a very simple diagram in which the various items or pieces of equipment are represented by a square or rectangular box. The purpose of the block diagram is to show how the components of the circuit relate to each other and therefore the individual circuit connections are not shown. Ill. 9 shows the block diagram of a high-voltage discharge lighting circuit.

Wiring diagrams

A wiring diagram or connection diagram shows the detailed connections between components or items of equipment. They don't indicate how a piece of equipment or circuit works. The purpose of a wiring diagram is to help someone with the actual wiring of the circuit. Ill. 10 shows the wiring diagram for a two-way lighting circuit.

Circuit diagrams A circuit diagram shows most clearly how a circuit works. All the essential parts and connections are represented by their graphical symbols. The purpose of a circuit diagram is to help our understanding of the circuit. It will be laid out as clearly as possible, with out regard to the physical layout of the actual components, and therefore it may not indicate the most convenient way to wire the circuit. Ill. 11 shows the circuit diagram of an n-p-n transistor test circuit.

Ill. 11 Circuit diagram of an n-p-n transistor test circuit.

TELEPHONE MESSAGES

Telephones today play one of the most important roles in enabling people to communicate with each other. The advantage of a telephone message over a written message is its speed; the disadvantage is that no record is kept of an agreement made over the telephone.

Therefore, business agreements made on the telephone are often followed up by written confirmation.

When taking a telephone call, remember that you can't be seen and , therefore, gestures and facial expressions will not help to make you understood.

Always be polite and helpful when answering your company's telephone - you are your company's most important representative at that moment. Speak clearly and loud enough to be heard without shouting, sound cheerful and write down messages if asked. Always read back what you have written down to make sure that you are passing on what the caller intended.

Many companies now use standard telephone message pads such as that shown in Ill. 12 because they prompt people to collect all the relevant information.

In this case John Pratt wants Dave Idiot to pick up the Megger from Jim on Saturday and take it to the Bowling Green site on Monday. The person taking the call and relaying the message is Dave Low.

When making a telephone call, make sure you know what you want to say or ask. Make notes so that you have times, dates and any other relevant information ready before you make the call.

Ill. 12 Typical standard telephone message pad.

WRITTEN MESSAGES

A lot of communications between and within larger organizations take place by completing standard forms or sending internal memos. Written messages have the advantage of being 'auditable'. An auditor can follow the paperwork trail to see, for example, who was responsible for ordering certain materials.

Ill. 13 Typical standard memo form.

When completing standard forms, follow the instructions given and ensure that your writing is legible. Do not leave blank spaces on the form, always specifying 'not applicable' or 'N/A' whenever necessary. Sign or give your name and the date as asked for on the form.

Finally, read through the form again to make sure you have answered all the relevant sections correctly.

Internal memos are forms of written communication used within an organization; they are not normally used for communicating with customers or suppliers. Ill. 13 shows the layout of a typical standard memo form used by Dave to notify John that he has ordered the hammer drill.

Letters provide a permanent record of communications between organizations and individuals. They may be handwritten, but formal business letters give a better impression of the organization if they are type written. A letter should be written using simple concise language, and the tone of the letter should always be polite even if it's one of complaint. Always include the date of the correspondence. The greeting on a formal letter should be 'Dear Sir/Madam' and concluded with 'Yours faithfully'. A less formal greeting would be 'Dear Mr Smith' and concluded 'Sincerely'…. Your name and status should be typed below your signature.

DELIVERY NOTES

When materials are delivered to site, the person receiving the goods is required to sign the driver's 'delivery note'. This record is used to confirm that goods have been delivered by the supplier, who will then send out an invoice requesting payment, usually at the end of the month.

The person receiving the goods must carefully check that all the items stated on the delivery note have been delivered in good condition. Any missing or damaged items must be clearly indicated on the delivery note before signing, because, by signing the delivery note the person is saying 'yes, these items were delivered to me as my company's representative on that date and in good condition and I am now responsible for these goods'. Suppliers will replace materials damaged in transit provided that they are notified within a set time period, usually three days. The person receiving the goods should try to quickly determine their condition.

Has the packaging been damaged, does the container 'sound' like it might contain broken items? It’s best to check at the time of delivery if possible, or as soon as possible after delivery and within the notifiable period.

Electrical goods delivered to site should be handled carefully and stored securely until they are installed.

Copies of delivery notes are sent to head office so that payment can be made for the goods received.

TIME SHEETS

Ill. 14 Typical time sheet.

A time sheet is a standard form completed by each employee to inform the employer of the actual time spent working on a particular contract or site. This helps the employer to bill the hours of work to an individual job. It is usually a weekly document and includes the number of hours worked, the name of the job and any travelling expenses claimed. Office personnel require time sheets such as that shown in Fig 2.14 so that wages can be made up.

JOB SHEETS

Ill. 15 Typical job sheet.

A job sheet or job card such as that shown in Fig 2.15 carries information about a job which needs to be done, usually a small job. It gives the name and address of the customer, contact telephone numbers, often a job reference number and a brief description of the work to be carried out. A typical job sheet work description might be:

An electrician might typically have a 'jobbing day' where he picks up a number of job sheets from the office and carries out the work specified.

Job 1, for example, might be the result of a blown fuse which is easily rectified, but the electrician must search a little further for the fault which caused the fuse to blow in the first place. The actual fault might, for example, be a decayed flex on a pendant drop which has become shorted out, blowing the fuse. The pendant drop would be re-flexed or replaced, along with any others in poor condition. The installation would then be tested for correct operation and the customer given an account of what has been done to correct the fault.

General information and assurances about the condition of the installation as a whole might be requested and given before setting off to job 2.

The kettle socket outlet at job 2 is probably getting warm and , therefore, giving off that 'fishy' bakelite smell because loose connections are causing the bakelite socket to burn locally. A visual inspection would confirm the diagnosis. A typical solution would be to replace the socket and repair any damage to the conductors inside the socket box. Check the kettle plug top for damage and loose connections. Make sure all connections are tight before reassuring the customer that all is well; then, off to the next job or back to the office.

The time spent on each job and the materials used are sometimes recorded on the job sheet, but alternatively a daywork sheet can be used. This will depend upon what is normal practice for the particular electrical company. This information can then be used to 'bill' the customer for work carried out.

DAYWORK SHEETS

Daywork is one way of recording variations to a contract, that's , work done which is outside the scope

++ Job 1 Upstairs lights not working

++ Job 2 Funny fishy smell from kettle socket in kitchen.

of the original contract. If daywork is to be carried out, the site supervisor must first obtain a signature from the client's representative, for example, the architect, to authorize the extra work. A careful record must then be kept on the daywork sheets of all extra time and materials used so that the client can be billed for the extra work. A typical daywork sheet is shown in Ill. 16.

Ill. 16 Typical daywork sheet.

REPORTS

On large jobs, the foreman or supervisor is often required to keep a report of the relevant events which happen on the site for example, how many people from your company are working on site each day, what goods were delivered, whether there were any breakages or accidents, and records of site meetings attended. Some firms have two separate documents, a site diary to record daily events and a weekly report which is a summary of the week's events extracted from the site diary. The site diary remains on site and the weekly report is sent to head office to keep man agers informed of the work's progress.

PERSONAL COMMUNICATIONS

Remember that it's the customers who actually pay the wages of everyone employed in your company.

You should always be polite and listen carefully to their wishes. They may be elderly or of a different religion or cultural background than you. In a domestic situation, the playing of loud music on a radio may not be approved of. Treat the property in which you are working with the utmost care. When working in houses, shops and offices use dust sheets to protect floor coverings and furnishings. Clean up periodically and made a special effort when the job is completed.

Dress appropriately: an unkempt or untidy appearance will encourage the customer to think that your work will be of poor quality.

The electrical installation in a building is often carried out alongside other trades. It makes good sense to help other trades where possible and to develop good working relationships with other employees. The customer will be most happy if the workers give an impression of working together as a team for the successful completion of the project.

Finally, remember that the customer will probably see more of the electrician and the electrical trainee than the managing director of your firm and , there fore, the image presented by you will be assumed to reflect the policy of the company. You are, therefore, your company's most important representative. Always give the impression of being capable and in command of the situation, because this gives customers confidence in the company's ability to meet their needs. However, if a problem does occur which is outside your previous experience and you don't feel confident to solve it successfully, then contact your supervisor for professional help and guidance. It is not unreasonable for a young member of the company's team to seek help and guidance from those employees with more experience. This approach would be preferred by most companies rather than having to meet the cost of an expensive blunder.

Construction site - safe working practice

Earlier we looked at some of the laws and regulations that affect our working environment. We looked at Safety Signs and PPE, and how to recognize and use different types of fire extinguishers. The structure of companies within the electro-technical industry and the ways in which they communicate information by drawings, symbols and standard forms was discussed earlier in this Section.

If your career in the electro-technical industry is to be a long, happy and safe one, you must always wear appropriate personal protective equipment such as footwear, and head protection and behave responsibly and sensibly in order to maintain a safe working environment. Before starting work, make a safety assessment. What is going to be hazardous, will you require PPE, do you need any special access equipment. Carry out safe isolation procedures before beginning any work. You don't necessarily have to do these things formally, such as carrying out a risk assessment as described in Section 1, but just get into the habit of always working safely and being aware of the potential hazards around you when you are working.

Having chosen an appropriate wiring system which meets the intended use and structure of the building and satisfies the environmental conditions of the installation, you must install the system conductors, accessories and equipment in a safe and competent manner.

(Various wiring systems were discussed in Section 1 under the sub-heading Industrial Wiring Systems).

The structure of the building must be made good if it's damaged during the installation of the wiring sys tem. E.g., where conduits and trunking are run through walls and floors.

All connections in the wiring system must be both electrically and mechanically sound. All conductors must be chosen so that they will carry the design cur rent under the installed conditions.

If the wiring system is damaged during installation it must be made good to prevent future corrosion. E.g., where galvanized conduit trunking or tray is cut or damaged by pipe vices, it must be made good to prevent localized corrosion.

All tools must be used safely and sensibly. Cutting tools should be sharpened and screwdrivers ground to a sharp square end on a grindstone.

It is particularly important to check that the plug top and cables of hand held electrically powered tools and extension leads are in good condition. Damaged plug tops and cables must be repaired before you use them. All electrical power tools of 110 and 230V must be tested with a portable appliance tester (PAT) in accordance with the company's Health and Safety procedures, but probably at least once each year.

Tools and equipment that are left lying about in the workplace can become damaged or stolen and may also be the cause of people slipping, tripping or falling. Tidy up regularly and put power tools back in their boxes. You personally may have no control over the condition of the workplace in general, but keeping your own work area clean and tidy is the mark of a skilled and conscientious craftsman.

Finally, when the job is finished, clean up and dispose of all waste material responsibly as described in Section 3 of Basic Electrical Installation Work -- Disposing of Waste.