House Mods - A Few Questions

[dumbrill]

My house is undergoing a few modifications and I have some questions on the work required. I’ve read various books, etc on the 17th Ed regs, but I’d be grateful of getting some clarifications or comments on the following:

The existing cables under the ground floor are run loose between the joists and lying on the concrete floor. Is this OK or should they be clipped, run in trunking, etc? Correcting this would require a lot of extra work!

I have determined that a 10mm2 earth bonding wire is required for the water and gas supplies and this is run back to the CSU. Nothing installed at the moment. This seems straightforward. However my understanding is that equipotential bonding in bathrooms, etc should not have an earth cable back to the consumer unit, but should instead be connected to the earth in the circuit nearby. Is this correct? Some of the existing equipontential bonding in the house does have its own connection directly back to the CSU, which I don’t think is correct.

I have a split load consumer unit: a 60A RCCB protecting ring mains and cooker with MCBs and the lights, alarm, central heating off the unprotected side with MCBs only.

I am also having a new bathroom installed. There is space to run the lighting, fan, shaver point, etc from a new circuit on the RCCB side of the consumer unit. I assume that there should be no issues with this, other than zoning requirements, etc.

I want a new radial circuit to feed only a double socket for the fridge/freezer, but without RCD protection. The cable will be run under the floor and up inside a stud wall. Taking into account safe zones and running 50mm below the surface I also understand that the cable will require mechanical protection (no RCD). In this case SWA cable would be an easy option. The run is only about 10m long.

 

[patricklondon]

if you post what area you are in maybe then some of the Part P registered electricians here can private message you with some contact details so you can get all the work done properly with certificates issued to the local building control as required

 

[dumbrill]

if you post what area you are in maybe then some of the Part P registered electricians here can private message you with some contact details so you can get all the work done properly with certificates issued to the local building control as required

I understand where your coming from, but this isn't really a question about not getting the work done correctly. It will be all subject to Building Control and if I did decide to do the work myself then I would have to pay the charge the council makes for testing. One way or another I recognise that I''m not going to get sign-off without it being done correctly. Whatever route I choose I still want to know the whys and wherefores of what needs to be done.

 

[Phil Mumford]

The cables should be clipped or supported in some way.

Mains bonding: yes. Supplementary: forget it. Not required as all bonded at boiler manifold or cylinder. Bond in the airing cupboard if you really want to.

All circuits in a bathroom should be RCD protected under the 17th. Fused spur off the ring main? Separate RCD outside bathroom? Move cooker off RCCB and remove socket outlet on CCU if present and put lighting circuit on RCCB?

Dedicated socket for fridge/freezer: If deeper than 50mm no need for mechanical protection or RCD. If less than 50mm mechanically protect. Label as dedicated socket for fridge (make it a single?). And connect to suitable MCB on non-RCD side of board.

 

[electricAl]

I understand where your coming from, but this isn't really a question about not getting the work done correctly. It will be all subject to Building Control and if I did decide to do the work myself then I would have to pay the charge the council makes for testing. One way or another I recognise that I''m not going to get sign-off without it being done correctly. Whatever route I choose I still want to know the whys and wherefores of what needs to be done.

When i first read thru your post i formed the impression you were attempting to verify that the work that you are having done was `up to scratch` - if so, not a bad idea atall.

However, your comments ^ suggest that perhaps you are in fact, another DIYer who totally underestimates the technical knowledge that competent electricians posess. If i`ve assumed incorrectly, then you have my sincere apologies - & please set the record straight - i`ll happilly eat humble pie.

But if the former is the case, then credit to you for informing yourself by reading up on the subject, but the rather basic questions you`ve asked, & the flawed assumptions you have made, tell me you need to study far more if you are proposing to safely do the work yourself. Anyone unable to pass a Regs course shouldn`t be installing electrics - whether for themselves or others. & Regs courses are laughably easy.

Part P does permit you to install bonding - whether that be Main or Supplementary. FYI the Main Protective Bonding SHOULD certainly run directly from incoming services to the MET, whilst, contrary to Phil`s post above, Supplementary bonding WOULD need to be carried out within, or immediately adjacent to, the bathroom. That would entail cross bonding ALL ccts of the location to each other, & to all extraneous conductive parts within that location.
Of course, it would be preferable NOT to have to do this, & it could be ommitted if all ccts OF the location are RCD protected, meet disconnection times, & are part of a equipotential zone with any extraneous parts effectively connected back to the MET (if you understand the significance of all that then you have learned a little of what you`ll need to know)
I suspect Phil was fuzzing the line between Main & Supplementary Bonding & recognised if your circuits comply under the 17th you won`t need Supp` Bonding anyway. However, your board is never gonna comply unless at least an additional RCCB is fitted (probably not possible anyway) or RCBOs are used - these would make a lot more sense for the Fridge cct than SWA (& the exception for labelled, non RCD protected S/Os was NOT intended for such appliances anyway - a common misconception)

But this is hopefully all academic.

From your OP you give the impression that SOMEONE else is fitting the bathroom - i assume you`re paying for their services. If so, i respectfully suggest that perhaps you should review your prioritisation. Or perhaps you feel there`s far more skill involved in fitting a sink than a circuit breaker...

I`d strongly urge you to approach a local, competent, Part P registered spark to quote you for the work (you may be pleasantly surprised at the reasonable prices - even tho he has to shell out £500 a yr to be Part P assessed aswell as test gear, van, tools, advertising, updating qualies etc)
& if funds necessitate, you could fit the sink/bath/tiles etc yourself - i`ve fitted plenty - they`re ruddy easy! plus they require little technical knnowledge & they can`t kill you nor your folk)

& then allow an experienced, qualified & capable (but seriously undervalued) tradesman to earn a living. And if he is a good un he won`t object to you looking over his shoulder,picking his brains or even mucking in with the dirty work. Then everyone`s a happy bunny (except maybe the bathroom fitter)

p.s. Good luck with the bonding if you do choose to do that yourself, & if you require any further guidance to this or any other appropriate tasks, then ask away & many of us will help you.