17th edition rewire

[andyandy2]

Now the 17th regs have been in for awhile, i was just wondering what is working out the "best working practice" in relation to consumer unit, and circuit protection.

We are just starting a rewire on a 4 bed detached property that has just been extended, some exsisting cable routes will be reused so normal twin and earth will be used and these circuits rcd protected,

My concerns are regarding nuisance tripping which could be caused by outside lights etc. are these better on seperate circuits with rcbo's

We also need to install an air pump for sewage treatment plant, instructions say to install on a seperate circuit, but am concerned that if for some reason it tripped the circuit we wouldn't know, my thoughts are to spur it from a ring main via an fcu (the pump is only low wattage)

The same concerns relate to smoke alarms, in the past i've connected them to the lighting circuit, is this acceptable ?

I've also been searching the forum with limited success regarding the use of junction boxes under floorboards for lighting circuits, are they classed as accessible ? I could loop into the light switches but was just thinking of saving cable really, and already numerous cables to some switches.

Any help much appreciated

 

[londonboy]

The best way would be to use RCBO's on every circuit, but at £25 each this works out very dear! I tend to use high integrity dual RCD boards, they have a few unprotected spare ways that you can use for things that don't need RCD protection.

I'd probably also fit a FCU for the sewage pump from the ring final (for the reasons you've stated).

Take smoke alarms from lighting circuit, this discourages homeowners from turning off alarm circuits.

Inaccessable junctions isn't allowed, although if you can pull the junction out of the ceiling I personally consider that acceptable. On future rewires I think I'll take the feed to the switches and loop, as you say.

Hope this covers your points.

 

[holmslaw]

..

 

[andyandy2]

Thanks londonboy

Holmslaw, why would i want to employ a good electrician to sort out simple problems, i though forums such as diynot are for advice, there are different ways of doing things i'm looking for ideas

 

[londonboy]

andyandy I (shouldnt have) assumed you know about part p and notifiable works etc.

 

[andyandy2]

Yes londonboy i'm aware of part p, have had arguments with building control in the past lol, its all going through building control as the house has just been extended

 

[londonboy]

Your probably in the only situation where your better off down the building control route, most of the time this works out too expensive for small works

 

[ban-all-sheds]

Holmslaw, why would i want to employ a good electrician to sort out simple problems,

Because they aren't simple enough for you to sort out yourself?

Doing a complete rewire is not something you should attempt on the basis of asking random questions as they happen to occur to you.

i though forums such as diynot are for advice

It is. Holmslaw advised you to get an electrician.

 

[andyandy2]

Holmslaw, why would i want to employ a good electrician to sort out simple problems,

Because they aren't simple enough for you to sort out yourself?

Doing a complete rewire is not something you should attempt on the basis of asking random questions as they happen to occur to you.

i though forums such as diynot are for advice

It is. Holmslaw advised you to get an electrician.

They are problems which can have various solutions hence why i asked for advice, Londonboy answered my questions with his chosen method, why can't you ?

 

[ban-all-sheds]

We are just starting a rewire on a 4 bed detached property that has just been extended, some exsisting cable routes will be reused

Are they allowable routes?

so normal twin and earth will be used

How have you sized the cables?

Have you considered other types of cable?

and these circuits rcd protected,

Do you want to RCD protect them all?

My concerns are regarding nuisance tripping which could be caused by outside lights etc. are these better on seperate circuits with rcbo's

Do you want to RCD protect those circuits?

We also need to install an air pump for sewage treatment plant, instructions say to install on a seperate circuit, but am concerned that if for some reason it tripped the circuit we wouldn't know, my thoughts are to spur it from a ring main via an fcu (the pump is only low wattage)

Do none of them have power loss alarms?

The same concerns relate to smoke alarms, in the past i've connected them to the lighting circuit, is this acceptable ?

You can look that one up in the Wiring Regulations.

I've also been searching the forum with limited success regarding the use of junction boxes under floorboards for lighting circuits, are they classed as accessible ?

Depends on the type of floor.

 

[andyandy2]

Ban please don't litter my thread with your constant endless quoting and answering questions with more questions, i'm just looking for alternative views and opinions on what works best in practice.

Yes the cables are in allowable routes
Cables are correctly sized for the circuits involved
Other types of cable have been considered
We are happy to rcd protect the circuits where we are using exsisting cable routes
The circuits i mentioned in the opening post are the ones i'm interested in
"Do none of them have power loss alarms" by this i presume you mean the air-pump itself, which was supplied with the treatment tank, it doesn't have a power loss alarm, can they be fitted ?
The smoke alarm question, seems to get different opinions, but i've not checked the regs.
The flooring is normal floorboards, sections have been removed by previous electricians /plumbers if i were to use junction boxes i would site them under one of these boards, boards would be covered with carpet, again there seems to be mixed views on this issue.

 

[ban-all-sheds]

Ban please don't litter my thread with your constant endless quoting

Don't tell me how I may or may not respond.

and answering questions with more questions, i'm just looking for alternative views and opinions on what works best in practice.

Those alternative views, and best practices, are influenced by what you want to do.

I was trying to find out what your requirements actually were, so I apologise for that, I hadn't realised that you wanted designs for the hard of thinking.