IET
Decrease font size
Increase font size
Topic Title: CU replacement.
Topic Summary: Like for like?
Created On: 13 March 2019 11:35 am
Status: Read Only
Linear : Threading : Single : Branch
1 2 Next Last unread
Search Topic Search Topic
Topic Tools Topic Tools
View similar topics View similar topics
View topic in raw text format. Print this topic.
 13 March 2019 11:35 am
User is offline View Users Profile Print this message



mikejumper

Posts: 2810
Joined: 14 December 2006

CU replacements are generally referred to as upgrades, but suppose you wanted to do a like for like replacement.

As with replacement of other items in the installation, I presume as long as the installation is not left in a less safe condition than when you started there is no reason not to do it.

What do you think?
 13 March 2019 11:45 am
User is offline View Users Profile Print this message



daveparry1

Posts: 8020
Joined: 04 July 2007

Are you thinking that being "like for like" it wouldn't be notifiable Mike? I don't think that would be the case as it's still replacement although I would be pleased to think it could be the case as i'm no longer a "scam" member! As it happens I've turned down four c/u changes this year already (and that's the number I done all last year before cancelling my registration). I suppose also it couldn't be deemed that much like for like or it wouldn't be being replaced, unless perhaps for damage reasons etc?
 13 March 2019 11:51 am
User is offline View Users Profile Print this message



chrispearson

Posts: 1095
Joined: 15 February 2018

Originally posted by: mikejumper

CU replacements are generally referred to as upgrades, but suppose you wanted to do a like for like replacement.


Part P sayeth:

Part P safety;
12. - (6A) A person intending to carry out building work in relation to which Part P of Schedule 1 imposes a requirement is required to give a building notice or deposit full plans where the work consists of -
(a) the installation of a new circuit;
(b) the replacement of a consumer unit; or
(c) any addition or alteration to existing circuits in a special location.


There is nothing there which excludes a like-for-like replacement.
 13 March 2019 11:52 am
User is offline View Users Profile Print this message



geoffsd

Posts: 2342
Joined: 15 June 2010

What do you mean? What have you in mind?

The requirement for notification states "The replacement of a consumer unit" as the criterion.

Nowhere is the phrase "like for like" mentioned; the term has always been "replacements". That you or other people regard things as "upgrades" has no bearing on the matter.

The regulations do mention "not left in a less safe condition" but why would you bother replacing something if it were less good or safe than before?
 13 March 2019 12:04 pm
User is offline View Users Profile Print this message



dustydazzler

Posts: 3068
Joined: 19 January 2016

'Like for Like' is too grey imo , as is new circuit for that matter ....

I can understand 'Like for Like' as in you remove say a B16 MCB and replace it with another B16 MCB , this to me is genuine Like for Like replacement...


But once you rip an old consumers unit off the wall and install a new one , its a brand new board and nothing really like the old one

You could argue that its 'Like' it was before , but I am not sure how that would stack up with PartPee
 13 March 2019 12:39 pm
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

Part P sayeth:

Part P safety;
12. - (6A) A person intending to carry out building work in relation to which Part P of Schedule 1 imposes a requirement is required to give a building notice or deposit full plans where the work consists of -
(a) the installation of a new circuit;
(b) the replacement of a consumer unit; or
(c) any addition or alteration to existing circuits in a special location.

Interesting ... so if I install a new CU alongside the existing one, connect it into the same supply circuit, and transfer some (or all) of the outgoing circuits to the new CU, then I've not installed any new circuits or replaced a CU - so as long as it's not in a special location, no notification is required?
- Andy.
 13 March 2019 12:54 pm
User is offline View Users Profile Print this message



dustydazzler

Posts: 3068
Joined: 19 January 2016

I believe this to be correct AJJ

The one caveat would be you would need to leave the old redundant fuse box on the wall just to prove you haven't replaced a consumers unit
 13 March 2019 01:12 pm
User is offline View Users Profile Print this message



daveparry1

Posts: 8020
Joined: 04 July 2007

Perhaps even feed the new c/u from the old one Dusty, via a 60 amp mcb?
 13 March 2019 01:21 pm
User is offline View Users Profile Print this message



dustydazzler

Posts: 3068
Joined: 19 January 2016

Originally posted by: daveparry1

Perhaps even feed the new c/u from the old one Dusty, via a 60 amp mcb?


I would never do such a thing to circumnavigate PartPee , not me Guv

Well maybe just once , or twice ....
 13 March 2019 01:25 pm
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

Perhaps even feed the new c/u from the old one Dusty, via a 60 amp mcb?

Wouldn't that fall under 'installing a new circuit' then though?
- Andy.
 13 March 2019 01:26 pm
User is offline View Users Profile Print this message



dustydazzler

Posts: 3068
Joined: 19 January 2016

Originally posted by: AJJewsbury

Perhaps even feed the new c/u from the old one Dusty, via a 60 amp mcb?


Wouldn't that fall under 'installing a new circuit' then though?

- Andy.


Not if the Mcb was already there
 13 March 2019 01:28 pm
User is offline View Users Profile Print this message



mikejumper

Posts: 2810
Joined: 14 December 2006

Originally posted by: daveparry1
Are you thinking that being "like for like" it wouldn't be notifiable Mike?

No, though I can see why you've asked that question.

For example:

Suppose you had an old Wylex CU with four 3036 fuses that has been damaged to the extent that it can't be used. You have an identical replacement available, if you fit it you are not leaving the installation in a less safe condition than you found it, in fact you'd be be making it safer. Is there any reason why it can't be fitted.

I guess the question I'm trying to answer is: Are we obliged to 'upgrade' a CU when we replace it?
 13 March 2019 02:15 pm
User is offline View Users Profile Print this message



geoffsd

Posts: 2342
Joined: 15 June 2010

Well, you would have to install it to the latest regulations - therefore it would have to be one of non-combustible material.


Incidentally, none of this has anything to do with Part P, which only says that work shall be done to ensure safety etc.
 13 March 2019 02:24 pm
User is offline View Users Profile Print this message



chrispearson

Posts: 1095
Joined: 15 February 2018

Originally posted by: geoffsd

Incidentally, none of this has anything to do with Part P, which only says that work shall be done to ensure safety etc.


My apologies for not being clear - I was following the Approved Document.

My quotation above was Reg 12 of the Building Regulations 2010 as amended.
 13 March 2019 02:27 pm
User is offline View Users Profile Print this message



chrispearson

Posts: 1095
Joined: 15 February 2018

Originally posted by: AJJewsbury

Interesting ... so if I install a new CU alongside the existing one, connect it into the same supply circuit, and transfer some (or all) of the outgoing circuits to the new CU, then I've not installed any new circuits or replaced a CU - so as long as it's not in a special location, no notification is required?


Well, yes, that regulation does not mention the installation of a new CU, but presumably that is to be found elsewhere.
 13 March 2019 02:40 pm
User is offline View Users Profile Print this message



chrispearson

Posts: 1095
Joined: 15 February 2018

Originally posted by: mikejumper

I guess the question I'm trying to answer is: Are we obliged to 'upgrade' a CU when we replace it?


That's a very different question, but we are obliged to fit one which complies with BS 7671:2018.

So could we fit an old plastic fuse box? Yes, but under very limited circumstances. First, it would have to be either enclosed in a non-combustible enclosure, or be outside domestic (household) premises (421.1.201). Second, the final circuits could not be soft cables in walls, etc. (522.6.202 - 204). Third, in a dwelling, any sockets would have to be RCD protected, either by an RCD in the circuit, or locally (411.3.3). Finally, similarly, RCD protection would have to be provided for any circuit which supplies luminaires (411.3.4).

An example might be a fusebox in a detached garage, with surface mounted wiring, with SRCD-protected sockets, and a single pendant lamp-holder.

But why?
 13 March 2019 04:15 pm
User is offline View Users Profile Print this message



mikejumper

Posts: 2810
Joined: 14 December 2006

Originally posted by: chrispearson

Originally posted by: mikejumper
I guess the question I'm trying to answer is: Are we obliged to 'upgrade' a CU when we replace it?

That's a very different question, but we are obliged to fit one which complies with BS 7671:2018.

In a new build certainly, but if we are replacing an existing CU, do the same rules apply? A like for like replacement is not making the installation less safe.
 13 March 2019 04:42 pm
User is offline View Users Profile Print this message



geoffsd

Posts: 2342
Joined: 15 June 2010

Don't keep saying like for like; it means nothing. It is a replacement.

A replacement CU would have to be to current regulations.
If you can find one with 3036 fuses that is non-combustible or build an enclosure then all well and good.

I don't think it would have to have RCDs - like replacing a shower or luminaire that is not on an RCD circuit.
 13 March 2019 05:34 pm
User is offline View Users Profile Print this message



alancapon

Posts: 7492
Joined: 27 December 2005

Originally posted by: mikejumper
. . . In a new build certainly, but if we are replacing an existing CU, do the same rules apply? A like for like replacement is not making the installation less safe.

True, but how are you going to ensure you don't connect any dangerous circuits if you don't test them?

This argument can only be decided by case law, and as far as I know, it has not (yet) been tested in court, which would be following an incident.

Regards,

Alan.
 14 March 2019 10:34 am
User is offline View Users Profile Print this message



Paradigm

Posts: 881
Joined: 10 September 2010

Originally posted by: alancapon



True, but how are you going to ensure you don't connect any dangerous circuits if you don't test them?


Regards,



Alan.


Well to be pedantic, if the circuit was already dangerous before you did anything, you havent made it any LESS safe which is the requirement of the regs.

I believe OMS used to use the case of a hospital where you hypothetically changed a major piece of switchgear at the main distribution point. You wouldnt then become responsible for a faulty circuit upstream in a building 100's of metres away that you had been nowhere near. Why would you be responsible for a poorly installed junction box hidden in a floor void under a bedroom carpet if you changed the CU.

I believe that the reason there hasnt been a test case is because its a non starter, its just another urban myth thats become standard wholesalers folklore due to being said so much and not questioned.

Regards

Nick

-------------------------
"be careful of what you write"
IET » Wiring and the regulations » CU replacement.

1 2 Next Last unread
Topic Tools Topic Tools
Statistics

New here?

  • To participate in discussions, please log in and introduce yourself.

See Also:



FuseTalk Standard Edition v3.2 - © 1999-2021 FuseTalk Inc. All rights reserved.

 
..