Ask me about automating your home

Part ‘P’ of the building regulations applies exclusively to domestic dwellings. Click on the ‘regulations’ link above for more details about what is and is not notifiable.

All work should also conform to the latest IET wiring regulations which are currently the 18th Edition 2018. There are other regulations applicable to domestic installations these include Part ‘B’ which states that there should be at least one mains powered smoke or heat alarm per floor and these should be linked so one detector will set the next off.


All these regulations are there to ensure your safety. It obviously makes sense to have RCD protection, protective conductors, cables run in safe areas and rated correctly to the load and protective device. If you were selecting a new car you would probably check it’s Ncap rating, how it survives a crash. Well you should take the same care when selecting an electrical contractor. Is my installation going to be safe and if I do something silly like stick a knife in the toaster to get the stuck bread out, will I get a shock? You may think it will not happen to you, well my son did the toaster thing and because we had an RCD he is still here to tell the tale!

Residual Current Devices come in many flavours but basically all do the same job. They detect electricity leakages, they do this by comparing what travels out through the live wire to what comes back through the neutral wire. They have a rating, 30mA is the most common. If they detect a 30milliAmp difference in what is going out to what is coming back they trip. Now it just so happens that 30mA is deemed as a ‘safe’ amount of electricity to flow through the body for 0.4 of a second. So RCD’s have to trip in that time or less. When one is installed it should be tested to ensure this is so. The test button provided on the device does not do this! It just checks that the mechanics of the switch are working correctly. The time and trip current has to be tested with a special meter.


Please contact me on

07799 767036 or

mick@mc-electrician.co.uk