module 8 / application of health & safety and electrical principles

Ways of taking precautions for risks.

If you take just a moment to think about what you are doing, or are about to do, you will find that you can avoid most potentially dangerous situations. Another of the most effective ways to reduce the risk of accidents is to try to remove the cause, such as storing conduit horizontally and locked away. Reporting potentially hazardous situations to your supervisor will be affective.

What are the important things to ask when carrying out a risk assessment?

• What are the actual and/or potential hazards?

• Are these hazards significant?

• Are the hazards covered by satisfactory precautions so that the risk is small or should new or revised precautions and/or procedures be put in place?

What is a hazard and a risk?

• A hazard can be defined as: anything that can cause harm (e.g. working from ladders or scaffolding, substances such as asbestos, chemicals, electricity, etc).

• A risk can be defined as: the chance, high or low, that somebody will be harmed by the hazard.

Step 1 of carrying out a risk assessment.

step 1 is looking for hazards.

Take a walk around the workplace. Look at what could reasonably be expected to cause harm. such as faulty electrical connections, damaged cables, materials that are ejected from machines, pressure systems. Also check with your employees, as they may have noticed things that are not immediately apparent to you.

Step 2 of carrying out a risk assessment.

Step 2 is decide who might be harmed and how.

Apprentices and trainees, young workers, new and expectant mothers etc., who may all be at particular risk. Visitors, contractors, cleaners, maintenance workers, etc., who may not be in the workplace all the time. All of these and more could be harmed.

Step 3 of carrying out a risk assessment.

Step 3 is evaluate the risk.

Evaluate the risks and try to decide if the precautions that may already be in place are adequate or if more should be done. Assess how likely it is that each hazard could cause harm. This evaluation and assessment will determine whether or not more needs to be done to reduce the risk. However, you must accept that even after all reasonable precautions have been taken, some risk usually remains.

Step 4 of carrying out a risk assessment.

Step 4 is to record your findings.

If you have 5 or more people in employment you must record any significant findings in your assessment, this means writing down the hazards and conclusions. You must also tell your co workers of this as well as keep the sheet in a safe place as it can protect you from a civil liability.

What you must record is: A proper check was made, you asked who may be affected, all the obvious significant hazards were dealt with, taking into account the number of people who could be involved and the remaining risk is low and the precautions taken are reasonable.

Step 5 of carrying out a risk assessment.

Step 5 is to review your assessment.

Sooner or later the existing situation will change. You will bring in different substances or procedures, or new machines that could lead to new hazards. If there are any significant changes, these should be added to the risk assessment to take account of the new hazard. However, if a new job introduces significant hazards of its own, you will want to consider each of these in their own right.

What causes most slip, trips and falls in the work place.

Most slips, trips and falls come from either lifting and handling, or working at heights. More than a quarter of all work related accidents are connected to manual handling.

Most causes can be due to:

• Fluids spilt on the floor

• Polythene sheeting that may be left lying around

• Projecting scaffolding poles and other objects

• The plastic strapping from around bricks or other packaging

• Trailing cables (one of the most common causes of trips)

Checks before lifting loads.

Before you lift any load you should always make the following checks:

Assess the weight, size and shape of the load.

Has it got sharp edges?

Is there somewhere you can put it down, either en route or when you get there?

Is the route free of obstructions?

Will the load fit through the doors and are the doors open?

What is a time sheet?

Timesheets are very important to you and your company. These are the permanent record of the work done on a site and include details of:

• Each job

• Expenses

• Overtime

• Travelling time

The information on the time sheet allows the company to track its costs and to make up your wages. If you work on several sites over the course of a week, you may need to fill in a separate timesheet for each job.

What is the purpose of a job sheet?

Some electrical contracting companies issue job sheets to their electricians. These job sheets provide detailed information about a job to be done. Job sheets frequently require the customer to sign them to indicate that the work has been done. Usually they will include:

• A clear description of the work to be carried out

• Any special instructions or special conditions (e.g. pick up special tools or materials)

• The customer’s name and address

What is the purpose of a variation order (VO)?

The purpose of the VO is to record the agreement of the client for any extra work to be done, as well as any change that this will make to the cost and completion date of the project. A variation order is issued when the work done is different, or varies, from the original work agreed in the contact and listed in the job sheet. This is done so the terms of the previous contract aren’t broken.

What is the purpose of a day worksheet?

Work that is done outside the original scope of the contract, perhaps as a result of a variation order initiated by the architect for example, is known as day work. Day work sheets are usually quoted at a higher price and need to be signed of by the client.

It is important that the installation team who are on site record any extra time, plant and materials that may be used when doing day work. Once work is completed, completed day work sheets need to be taken to a office receipt.

What is the purpose of a purchase order?

Before a supplier will send out any materials or equipment, they will require a written purchase order. The purchase order should include details of the material, quantity required, and may (sometimes) specify a particular manufacturer.

The purchase order may also specify a delivery date and address. Purchase orders may be created from phone calls, emails websites etc,. A conformation code will be sent to the client right after.

What is the point of a delivery note?

Materials delivered directly to a site will arrive with a delivery note. The delivery note should contain the following information:

• A list of the type, quantity and description of any materials that are being delivered in this particular load

• The name of the supplier

• The time period allowed for claims for damage

• Who the materials are being sent to

When materials arrive on site you should make sure you try to do the following:

• Check each item against the delivery note.

• Check for obvious signs of damage.

• Ensure that they are unloaded and stored correctly.

What is the purpose of a site report?

Site reports contain details of work progress, defects, problems and delays and most companies require regular reports about the progress on site. Sometimes additional reports on particular problems or incidents will be made and such reports may enable the company to:

• Provide evidence when they make claims for progress payment

• Spot problems that keep being repeated and take action to eliminate them

• Take prompt action to avoid any difficulties that may be building up

Site report memo is usually short and brief, normally about a single issue such as materials not being delivered on time or a particular safety issue.

How transferring measurements in a diagram are used.

Scale drawings are used for planning and preparing an installation. Scaled drawings use fixed ratios, for example 1:150. This would mean that every 100 mm on the drawing is 150 times bigger in reality. Scaled drawings can therefore be used to plan detailed installations in advance.

How to take recording in-site measurements for materials for a job.

When you arrive on a site to take measurements it is always best to carefully record them in a notebook, and keep this safe. If you measure incorrectly of forget the measurement It could mean that you order too much or too little material. That is why its best to write down the measurements and to keep it safe.

If you are required to carry out measurements on site, there are a number of tools that you can use to help, such as long measuring tapes and laser distance measurers.

How to prepare a materials list for a new project.

If you are working for a large contractor you would probably be able to order the materials needed from a central store. If not, then you could order them directly from a local wholesaler. In either case, the process of working out what you need is exactly the same.

The first thing to do is to get a copy of the layout drawing. As it would be a scaled down drawing it is possible to take measurements from the diagram and work out the actual dimensions of the building, so that you can prepare a materials list for the job.

Step 1: Count up all the major pieces of equipment needed

Step 2: Decide the best runs of conduit and trunking

Step 3: Calculate lengths of trunking, conduit and cable required

Step 4: Include accessories, fixings, etc.

Step 5: Consider special access equipment like a ladder.

4 Key tips to presenting the right image.

• knowledge, being able to answer all types of questions and to convey your answers in great description will show who ever you are talking to that you are very experienced and knowledgeable. This can give a good lasting impression on who ever you are talking too.

• Confidence, Being confident enables who you are talking to, to be insured and trusting in you as they will feel that they have gave their project into the right hands. This will make the progress go a lot more smoothly.

• Appearance, Looking business like will set the conversation in a good way as the clients first impression on you will be enticing to do business even if they don’t mean to judge you.

• Attitude, being kind and well mannered will be appreciated by the client as talking to you about he installation because it will reassure them and they will trust you know what you are talking about.

How does an AC generator works?

AC generators are normally produced by magnetism. As the magnet begins to rotate around the loop, starts to pass through the lines of flux (magnetic field). This is when we start to introduce electromotive force (emf).

maximum induced emf will occur when the magnets travel 90 degrees and the loop will have cut through the maximum lines of flux. As we keep on rotating the number will gradually reduce to zero as the loop lies between the lines of flux.

The magnets have now completed a positive half cycle. If we repeat the cycle the emf will be induced into a negative half cycle. If we were to put this cycle into a diagram it would be called a sine wave.

How is an AC generator shown on a diagram?

A peak value on a diagram is when the loop starts rising from zero as it cuts through more lines of flux until it reaches its maximum at 90 degrees. However, as it begins to fall it starts to complete a 180 degree until it starts going into another direction. These two mirrors are known as half cycles.

These opposite directions of the induced emf will still drive a current through a conductor, but that current will alternate as the magnets rotate. The current will always be flowing in the same direction as the induced emf. This causes the current to rise and fall in the same way as the induced emf and, when this happens, we say that the half cycles are in phase with each other.

The number of complete revolutions (cycles) that occur each second is referred to as the frequency, and is measured in hertz (Hz) and given the symbol f. The frequency of the supply in the UK is 50 Hz.

How do you calculate the average value (rms) of an AC generator?

As with the average of anything, the more values or samples that are used, the greater the accuracy. However, for a sine wave the RMS is always the peak value divided by the square root of 2. Dividing by the square root of 2 (roughly 1.414) is equivalent to multiplying by 0.707 (which is 1 divided by 1.414). As a formula:

Vrms = Vpeak X 0.707

Irms = Ipeak X 0.707

What is known as the voltage measurement from positive to negative peak?

Its known as the peak to peak value.