by mraich »
Tue Jun 17, 2008 10:40 pm
[quote="ericmark"]As to 10 or 12 way it would depend what you intend to put in it. I have seen the door bell transformer being put directly in the consumer unit. The distance above floor is Part M not 17th Edition and reading it again it does not seem to cover consumer units as such. The 17th Edition allows sockets for connecting caravans to be 0.5 to 1.5 meters more if flooding is likely which makes sense to mount high if you don’t want children to play with them. But of course it needs to be in a position it can be worked on. As to smoke alarm all new houses are required to have mains powered although battery backed smoke alarms and to supply these from a supply which could be tripped out due to a faulty appliance being plugged in is not allowed. And anything planned before 1st July does not have to be to 17th Edition even if completed after that date but I think you would be silly not to comply with 17th Edition.
At the moment working out exactly what is required for 17th Edition is not easy. The main thing is now it has been made plain that division of supply into circuits to avoid hazards and minimize inconvenience in the event of a fault includes the RCD. And if for example a circuit was to supply an item likely to have high earth leakage such as a cooker with mineral insulated rings then it should be on its own RCBO but if it were to have a ceramic hob these don’t suffer in the same way from hydroscopic problems so it could be combined with other circuits. But when the house is being built the type of cooker being fitted could be unknown so no one is sure what will become the norm. We have seen the same problems with this carbon foot print rating where they take into account the rating of stand alone fridge and freezers which are not being sold with the house. I got my copy of the 17th Edition in February and I am still finding bits I had not noticed and am still revising what is allowed. There are some mistakes for example no allowance was make for the use of SELV cables in a house and to follow the regulations to the letter all telephone, networking, Door bell cables and the like would need to be on the surface as they don’t use an earth system so neither an RCD or a cable surrounded with a earthed sheaf will work. This is an oversight and I am sure it will be corrected soon but it means until the update is published no one is quite sure what other changes may also be included in the first revision so we must use some common sense rather than blindly following the regulations to the letter.
Yours Eric[/quote] Once again, Eric, my thanks. You're a star. Also your response to my question on underfloor heating. I may impose upon you again when I come up with more 17th edition questions. As the old saying goes - if you want something done, ask a busy person. You're that busy person.