30mA RCD as main switch

[leep82]

Done a little bit of searching and found that a situation such as the title of this thread would be against current regs, heres my situation. Been to look at a few jobs on a bungalow. The customer wants lights on there garage, ( which already has a supply present), an outside socket, and an extra lighting point in there living room. Currently the installation has no RCD protection whatsoever. Supply is TNCS and feeds a DB with only 5 circuits ( sockets, cooker, lighting, garage and burglar alarm ). Could it be argued that i have improved the state of the installation and note it as a deviation if i fitted a 30mA RCD as the main switch. Its just that cost is a big issue for the customer and i already have in my possesion the RCD so this would be much cheaper than going down the 3 separate RCBO's route for the individual circuits i would be working on.

 

[leep82]

And what about the bonding?

bonding is fine

 

[uksparks]

3 RCBO's maybe £45 in total with a bit of looking around.

Really? Sounds a bit cheap...

 

[NickD]

Sixteen quid for an RCD FCU from Screwfix sounds cheaper.

 

[Darkwood]

I wouldn't say I'm a preacher of doom, but I do attend a fair number of domestic callouts and can honestly say the clients are always far less happy when they've lost the whole house or half of the house than when it's just one circuit out!

If they were living there when the electrics were fitted then the Electrician has failed to explain the pro and cons regarding the install and the alternative but usually more costly options available. I'm not a fan of arrive-fit and walk sparkies who don't interact much do it pretty much how they want it and just say thats how it is when these nuisance trips occur, that's not professional and reflects on the industry... people skills is as much part of being competent as the electric side.

If they moved in and it was like that already then quote them happy... yes I get the same customer in my field wanting to know why this why that and its annoying ... they get told the cost to improve or fix the situation and that's where the complaining stops about it been a nuisance. I didn't fit the set-up so not my fault but I can improve it.

Had a friend who couldn't find his torch and banged his head trying to reset the lighting breaker ...wanted it sorting as cheap as possible .. fitted a E/M light fed of the breaker on the cellar steps ... he's happy and is making the transition to low energy lamps too to help matters and didn't have to overhaul anything ... each job as you find it, one solution doesn't fit all.

 

[NickD]

Had a friend who couldn't find his torch and banged his head trying to reset the lighting breaker ...wanted it sorting as cheap as possible.

Hard hat.

 

[Darkwood]

Hard hat.

He can't find his 1million candle torch I really aint going to hold out on him having never mind finding his hard hat :6:

 

[Darkwood]

When ever I do a domestic I normally design it to the highest measure regarding protection then inform the customer I can cut cost but at a cost to the way the system works...

I use split boards with additional unprotected ways in these I fit RCBO's for:-

Security alarm.
Freezer
Boiler
Garage

The rest shared between the 2 rcd's

Explaining I can reduce the bill by up to £100 pounds and explaining the the issues in doing so often is good enough for the customer to go for my design, if you loose one freezer full of food it tends not to be worth the claim through insurance be would pay for the whole additional costs on its own, let the customer decide and have a pre-drafted options chart, they tick the extra they want they feel in charge and can't ever complain if they get nuisance tripping as its been explained and is in writing.

 

[davesparks]

A house owner having to get a sparks out in the rare worse case scenario where they cant reset is a minor disruption and inconvenience as its a rare occurance, where as telecom exchange losing its main servers and cutting of half a city is a major disruption whether rare or not ... you forget the regs cover domestic, commercial and industrial and looking at this regulation in the bigger picture will give better guidance on when to apply it.

Yes the regulations apply to all installations of any size, but they apply to each installation on an installation by installation basis. I agree that in the grand scheme of things one house losing power is a minor inconvenience, but by the same token is that one telephone exchange cutting off half of a city not a minor inconvenience compared to half of the country being cut off? And as far as I am concerned my whole house going off is a major inconvenience wheras I couldn't give two hoots about half of some city miles away losing its communications.

Each installation should be considered in its own right as an installation, and from the point of view of the installation all circuits going off at once is more inconvenient than just one going off, I hope we can all agree that this is true?
Your point, if I have understood you correctly, is that the greater inconvenience when considered alongside the likelihood of it happening is not significant enough to be overly concerned about.
I agree to an extent, I certainly wouldn't 'condemn' an installation for having a single RCD as a main switch or two RCDs or whatever but I would not install it like that and wouldn't ever recommend it.

When you get a sparks who solely works domestic then its easy to forget the regs cover a wider field and can lead to mis-interpreting and over applying of some regs.

I think you have struck on the underlying problem there, we have a set of regulations which can be mis-interpreted or over-applied and contain so many grey areas and mistakes.

 

[Darkwood]

Its the problem with the regs ... its design on a wide scale thus can't be written for individual set-ups in most cases and where it does address individual set-up it can take a whole section up so imagine it trying to cover the 3 sectors at a more detailed level ... it would be enormous and even harder to locate regulations ... its a trade off of detail against broad scope.

Agree the interpretation bit is key and what is a minor nuisance to one person could be a major to the next but we also have to keep a balance too hence my post 37.... design to the best without going to the full rcbo boards (no chance of getting these quotes) and then present the options, the customer has all the required info and also weighs up their own needs of the install, communication is key there should be no customer out their unaware about what they are paying for and what they sacrificed in going cheaper, if this is the case the Electrician has failed to involve the customer in the design stage and/or failed to explain the pro's and cons.

Key to getting this regulation been complied to is circumstantial and relies on getting the customer involved at key points and ensure they understand the install they are getting.

As you imply what is classed as inconvenience and a nuisance to one is not necessary the same for the next... but my post regarding the larger picture still applies to a certain extent as it was mainly why the regulation was introduced to allow firms to lay blame where financial costs and major disruption arose from poor design, its rare for a homeowner to run an Electrician through the courts because he lost all his power because the board did what it was supposed to..unless exceptional his case wouldn't stand.

 

[Lucien Nunes]

things like rcbo for boiler become a forethought so a vulnerable person doesn't lose heating if a fault occurs on a non related circuit they can't reset

I'm with DW on this but the above point can be quite important even in a domestic install because heating failure can lead to serious illness or death. If the main heat source is GCH, when the whole installation is dead they can't use either gas or electric heating. If only one circuit fails, one or other heat source will probably remain available. I'm conscious of this point because of my dad, who cannot withstand losing the heating for even a short time in winter. It's the main reason they have a standby generator!

 

[davesparks]

design to the best without going to the full rcbo boards (no chance of getting these quotes) and then present the options, the customer has all the required info and also weighs up their own needs of the install, communication is key there should be no customer out their unaware about what they are paying for and what they sacrificed in going cheaper,

I almost always fit RCBO boards, I do however fully discuss things with the customer and not just for the CU but for everything. I have won jobs despite being the higher quote on occasions because of this.
But like everything there are other factors to consider, I get all my work through recommendations so have an advantage there to start with. Plus I don't do a lot of domestic work and what I do do is smaller jobs and not new houses or whatever.

 

[HappyHippyDad]

Really? Sounds a bit cheap...

1. 32A wylex RCBO £12.99 (new) Wylex Nhx 32amp 30ma Type B Rcbo | eBay
2. Starbreaker RCBO £12.99 (new) Crabtree Starbreaker RCBO Choice 6Amp, 16Amp, 32Amp, 40Amp **NEW** Type B | eBay
3. 6a Wylex RCBO (new) £16.20 NEW WYLEX 6A TYPE B RCBO NHXSBS1B06 | eBay

Total price £42.18

ps.. Took me 5 minutes!

 

[baldsparkies]

If the alarm system has a dedicated circuit, chances are the reference methods used would not necessitate the use of an rcbo or rcd.
A correctly rated MCB on high integ would be within regs.
A good solid earth at the panel, assuming its a metal enclosure, and satisfactory earth loop, is always the primary concern.
To much blanket RCD protection these days.