Replacing rewirable fuse consumer unit with RCD - What tests to determine suitability

[electek]

Hi All,
My parents house has an old style rewirable consumer unit and i was considering replacing it with split load unit (obviously with RCD) to update to current regs.

Regarding testing wiring before replacing the consumer unit to avoid problems (nuiscance tripping e.t.c.) , is it just a case of carrying out insulation resistance tests on all the individual circuits that the RCD is going to protect ?

I assume any reading over 1meg between line / neutral/earth will be sufficient to prevent any problems ?

Any help and advice much appreciated.

Cheers.

 

[GaryM]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

You really need to be inspecting and testing all circuits for which you're going to be changing the protective devices for to ensure they're fit for continued service.

I normally carry out a Periodic Inspection Report on an installation prior to changing a consumer unit.

 

[darking]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

Hi electec! There is no such thing as a 17th (or any other Edition) consumer unit. There are five basic conditions that must be met by your installation of your new Consumer unit.

1) Reg 314.1 circuits should not be connected to a single upstream RCD

2) Reg 314.2 separate circuits must not be affected by the failure of other circuits

3) Reg 411.3.3 socket outlets for general use must have RCD protection

4) Reg 522.6.6 unprotected cables buried less than 50mm deep in a wall must have RCD protection

5) Reg 701.411.3.3 all circuits in a location containing a bath or shower must have RCD protection

Each of these conditions need to be met for your installation to be fully compliant, but without knowing the specific circuits supplied by your consumer unit and how many RCD's it has, I cant give better advice as yet.As pointed out by Gary, you need to issue an Electrical Installation Certificate

good luck mate

 

[bugsy]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

Initial test N/E at C.U. ( this will identify if any faults, )
If you have detected a fault test individual circuits to identify, sort problem.
Then test all circuits I/R
check your bonding conductors.( take app. required action )
There is a download on NIC EIC site , if you can't access it let me know i'll post it for you

 

[ezzzekiel]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

lot of guys carry out full periodic before a board change, personnally i would do full ir test and ring final test as a minimum as these will normally be your problem areas

 

[JT C]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

Sorry but if you are replacing a c/u then you need to be part P registered and if you are part P registered then you should know the answer.

 

[GaryM]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

That's incorrect.

An application for notification can be made to your local LABC.

 

[darking]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

JTC anybody in the UK can do any installation work on their own premises, but with Part P you can self certify your work.

Work controlled under Part P is therefore subject to notification to and inspection by, building control bodies. However, calling in a building control officer takes time and costs money. The solution to this problem is self-certification. Either way make sure that it is properly installed and an Electrical Installation certificate issued by a competent person.

 

[roukel01]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

JTC anybody in the UK can do any installation work on their own premises, but with Part P you can self certify your work.

Work controlled under Part P is therefore subject to notification to and inspection by, building control bodies. However, calling in a building control officer takes time and costs money. The solution to this problem is self-certification. Either way make sure that it is properly installed and an Electrical Installation certificate issued by a competent person.

I know plenty of electricians that do not agree with the 'Self Certification' schemes (or scams as they refer to them) and simply explain to customers the cost to register work with Building Control. They get along just fine and have never had a problem.
I admit, these sparks tend not to do the smaller jobs where paying £80 to sign off simple work in kitchens and bathrooms isn't cost effective, they seem to do the full re-wires etc where you can justify the cost.

 

[darking]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

Part P is now enshrined in the law under the Building act. Breaking the law is never a good idea.

I have a personal dislike for the whole way Part P is administrated. It was designed for plumbers and air condition folk so they could install their kit and wire it into the installation.

Instead it has spawned a lot of “domestic installers” who do a short EAL course and a 20 question exam on Part P and then become legally deputised cowboys. Real electricians with proper qualifications become hampered by all the red tape and extra cost.

But that is how the law has determined competency to do domestic installation work and obtain self certification .status. Get over it

 

[steviesparks]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

Hi electec! There is no such thing as a 17th (or any other Edition) consumer unit.

Try this........MK Sentry 17th Edition Consumer Units

 

[dufjax]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

Try this........MK Sentry 17th Edition Consumer Units

That's a marketing gimmick
These board only just scrape through the requirements of the 17th.
You ideally should be using RCBO's on every way to give protection.


**** I'm not dissing MK or any other "17th edition" board **** Just pointing out what the regs state about fault discrimination


Jim

 

[darking]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

hi Jim

I quite agree. If steviesparks had read my whole quote which said "Hi electec! There is no such thing as a 17th (or any other Edition) consumer unit. There are five basic conditions that must be met by your installation of your new Consumer unit.

1) Reg 314.1 circuits should not be connected to a single upstream RCD

2) Reg 314.2 separate circuits must not be affected by the failure of other circuits

3) Reg 411.3.3 socket outlets for general use must have RCD protection

4) Reg 522.6.6 unprotected cables buried less than 50mm deep in a wall must have RCD protection

5) Reg 701.411.3.3 all circuits in a location containing a bath or shower must have RCD protection

Each of these conditions need to be met for your installation to be fully compliant, but without knowing the specific circuits supplied by your consumer unit and how many RCD's it has, I cant give better advice as yet.As pointed out by Gary, you need to issue an Electrical Installation Certificate." he would have realized exactly what you had to explain to him

 

[Des 56]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

Hi electec! There is no such thing as a 17th (or any other Edition) consumer unit. There are five basic conditions that must be met by your installation of your new Consumer unit.

1) Reg 314.1 circuits should not be connected to a single upstream RCD

2) Reg 314.2 separate circuits must not be affected by the failure of other circuits

3) Reg 411.3.3 socket outlets for general use must have RCD protection

4) Reg 522.6.6 unprotected cables buried less than 50mm deep in a wall must have RCD protection

5) Reg 701.411.3.3 all circuits in a location containing a bath or shower must have RCD protection

Each of these conditions need to be met for your installation to be fully compliant, but without knowing the specific circuits supplied by your consumer unit and how many RCD's it has, I cant give better advice as yet.As pointed out by Gary, you need to issue an Electrical Installation Certificate

good luck mate

Underlined is an interpretation of these regs

No 1
It doesn't quite say that though
A TT system where there is a metal clad consumer unit, twin Rcds and a time delayed Rcd for the whole installation is compliant
This one I interprit more as Granny mustn't be allowed to fall down the stairs when the washer goes haywire,not that a single Rcd is not permitted
The twin Rcd boards go a long way to fulfilling this reg,however the Rcbo route does it better
The twin Rcd is the industries get out clause when it was realised that the new regs suggested what you have written,but has been found to be too expensive to take on board generally

No 2
That I interprate more for an installation with a fire alarm system rather than a domestic


Even with Rcbos Granny could still fall down the stairs if the landing light goes out,so its a case of minimising inconveniance as much as possible and twin Rcd boards are the cheapest method used at the moment to fulfill those requirements

 

[darking]

Re: Replacing rewirable fuse consumer unit with RCD - What tests to determine suitabi

1) So with twin Rcds and a time delayed Rcd for the whole installation is making the point of not having a single upstream RCD. I absolutely endorse RCBO's for every circuit, hence my 5 point comliance suggestions

2) Being under the 314 Division of installations part of the regs if you wish to apply this to fire detection surely domestic smoke alarms, properly wired in, would apply?. apart from the fact that granny is probably completely deaf, its about its about due account being taken of the consequences of the operation of ANY single protective device. Anyway with proper division of circuits there would be a hall and downstairs light, a landing light and a stairwell light. Anyone going out would not affect the other/s. Or is granny blind as well?