A problem that I always encounter during my sub contracting days is the pricing of my projects. Lots of my customers complains that I over charges them. At that time, the market rate for installing an additional 13 amps switch socket was 50 bucks for one additional point. More often than not, if the call was just to install one point, I would likely to loose money if I were to take into account the transport, labour and material charges, but as I am doing business in a rather small town, I have to keep them happy, hoping that something major can come from them or from their recommendations.
Now for a 50 ringgit a point, if there is more than 3 points. I can break even, the problem starts when competitors starts to undercut the prices by offering to to the same job for 35 ringgit. Most of the time, I will lose out because the house owners does not realise that they have been shortchanged.
The regulations set by the National Electrical Board states clearly that all switch socket circuits cannot exceed 2 points for one circuit. That means for every 2 socket points, there must be an individual circuit controlled by an individual circuit breaker. So for every 2 socket points, all the wires must go to the Main Panel so that the circuit could be properly protected by a 13 amp circuit breaker in case there is an overload.
Don’t get Shortchanged Due to the Lower Price.
What those unscrupulous contractors do is they looped all the three or four socket points into a single circuit. When there should be 2 circuits going back to the main panel, they have only one circuit of wires. Imagine the amount of wires they will be saving. This is a very dangerous practise and that is the reason we always see houses get burnt down due to electrical overloading.
First, the size of the wires won’t be able to take the amount of current used if all 4 of them are used simultaneously. Then the circuit breaker will heat up. The wires clumped together at the main panel will start to melt, and fire will result.
So the next time you are renovating, be suspicious when someone quotes you very much lower than others. Tell him you want it done according to specifications.
The correct specification for a normal household switch Socket points:
2 plug points to a circuit. That means if you have 4 extra plugs you must see 2 extra circuit breakers in your main panel. There should be six new wires running from the plugs to the main panel because you need 3 wires plus the green Earth wire, to make a complete circuit.
The size of the wires is 2.5 mm for switch sockets. Anything smaller will overload the wires and they will melt if used over a duration of time. It must also be double insulated if they are not in conduits. That means you should see two layers of insulation covering the bare copper wires. However you can request the wires to be placed inside conduits. If that is the case, a single insulation should suffice.
How to determine the Size of the Wires
All new rolls of wires come with a label wrapped together. Check the labels if you are around to supervise the job. However, many contractors do have wire leftover from other projects and these wires have already been unwrapped. If you are really the suspicious kind and don’t trust the contractor too much, you can always cut a short piece and go enquire with some electrical shops dealing in electrical wires. An experienced electrician can tell the difference just by looking at the wires.