by ericmark »
Sat Feb 16, 2008 10:09 pm
In general when wiring a garage one must allow for it becoming a laundry room with washing machine and tumble dryer so would allow for a 32 amp supply. If not attached to the house then some method of reducing the power available for the lights for example a consumer unit. And since there may be some rough work are cables will need protecting. The use of conduit and or steel wire armoured cable would be likely and due to current draw the volt drop and the earth loop impedance would need calculating in order to select the cable. Depending on how close to the house and what type of supply feeds the house earthing arrangements would have to be selected. Either TT or TN-S and this would also have a bearing as to if 2 or 3 core cable is used. When an electrician visits he will have most likely done similar jobs in the past and will not need to work things out before hand but will be able to plan using past experience being reasonably sure when it is all tested it will pass. You however will need to submit your plans to building controls before you start to comply with Part P and will need to prove you are competent to do the job. Then on completion you will need to measure all the impedance and or resistance of cables used and complete the forms showing all your test results. If you think you can complete this then all well and good but if not then better to get an electrician to start with. He may allow you to labour for him digging holes etc. So reducing the cost but if he is to sign the completion paperwork he must have been in control even if he did not do it all himself.
