• Welcome to the new forum. We're now hosted on ElectriciansForums.net rather than ElectriciansForums.co.uk - Chat about the forum upgrade by CLICKING HERE

Welcome to our Electrical Forum - We started out providing electrical advice just for the UK - But now we have specific advice for the USA too! - Register for free and share American Electrical Advice.

Discuss New consumer unit, builder says upgrade supply in the Electrical Forum area at ElectriciansForums.net

pariah66

EF Member
Hi

As part of a loft conversion to my 2 (now 3) floor flat in a Victorian Terraced house I have added about a dozen 2-gang sockets, a shaving socket, and about 16 downlights to my new floor, plus swapping four pendant lights for 16 downlights in the floor below.

An electrician was installing a new consumer unit today and then I got a call from the head builder who is not onsite. He told me the electrician is concerned that the main service feed coming into the fuse/meter is only 10mm across. The electrician has apparently wired and tested everything (even though he's left the ground floor lights not working) but says we can't turn on the power in the loft as he is not confident the consumer unit will not burn out or the RCDs will be constantly tripping as the mains service cable is too thin.

The head builder told me I will probably have to upgrade my supply. He started advising me to call The National Grid (I think he means UK power networks).

I checked the main feed wire and by my measurements it looks around 12mm across. My builder was saying it should be more like 35 mm across and they'd never seen this before.

I apologise for the lack of detail but that's literally all the information I have aside from two photos of the set-up which are attached.

The reason I am posting is this all seems very light on detail. For instance I would expect a bit more calculation and maybe some figures to justify why we need to shell out many thousands potentially to upgrade the supply. The same amount of people will be living in the house, there are just likely to be a few more lights on and maybe an extra device plugged in.

Could anyone offer any advice about this? Should I just accept it, should I ask UK Power Networks about it, or should I be asking for more detail about how he came to this conclusion (and if so, what?)? Do the photos suggest what we have is obviously wrong? Any pointers would be much appreciated


cheers,
Pariah66

20190523_200455.jpg

20190523_204630.jpg
 

Matthewd29

Regular EF Member
I have never ever came across a house or flat fed by a 35mm cable it's unheard of. 10 or 16mm is usually correct if in a flat maybe 25 if a house sometimes. Ask him for his calculations as realistically unless you have electric heating or showers there shouldn't be an issue. Do you have electric heating or shower(s)?
 

pariah66

EF Member
I have never ever came across a house or flat fed by a 35mm cable it's unheard of. 10 or 16mm is usually correct if in a flat maybe 25 if a house sometimes. Ask him for his calculations as realistically unless you have electric heating or showers there shouldn't be an issue. Do you have electric heating or shower(s)?
 

Charlie_

Electrician's Arms
Who installed the consumer unit?
You do need to get the incoming set up sorted out though.
That pyro needs to be glanded into a proper enclosure and then the tails need to be upgraded.
The dno will possibly insist on the pyro being replaced.
 

Murdoch

Electrician's Arms
That’s not the way to protect cables entering a fuse board

Can you post a picture showing the top face?

Doesn’t inspire confidence in the installer
 

westward10

In echoed steps I walk across an empty dream.
Staff member
Moderator
Sounds like you need to get an experienced electrician involved because from what you have said and shown that is currently not the case.
 

Wilko

Electrician's Arms
Hi - sorry to start off on a downer, but that’s a pretty sad job of a new CU installation. Yes, by all means have UKPN attend and review their side of things.
 

westward10

In echoed steps I walk across an empty dream.
Staff member
Moderator
From your picture you have several issues which need addressing and an experienced, qualified electrician would have addressed these prior to starting the works. The picture of the consumer unit clearly indicates your so called electrician has limited skills and debatable qualifications.
 

Charlie_

Electrician's Arms
In the meantime do not touch or move any of the existing cables, especially the main incoming pyro cable.
 

pariah66

EF Member
Thanks everyone. The electrician just installed the consumer unit. The rest has always been like it.

Am I right that there are two issues here?

1. The pyro (what is this?) needs to be glanded, earthed and tails need to be upgraded. Who would do this, the electrician, the DNO or the electricity supplier?

2. The cables going into the consumer unit need compression glands.

In addition, so far, no-one has seen anything here which suggests I need to upgrade the feed, does anyone know what questions I should be asking this electrician or what calculations I should ask him for?

I'll provide a photo of the top of the CU in the morning as I have no lights downstairs at the moment.
 

Baddegg

Still simmering Ken, not boiled yet buddy x
Electrician's Arms
Your builder and electrician are idiots and seeing that Cu install i would be concerned if he’s touched anything else!
 

Electrician Talk

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
Electrical 2 Go - Electrical Supplier and Electrical Wholesalers
Electrical Insurance
ElectriciansForums.net (formerly known as ElectriciansForums.co.uk) was setup in April 2006 to provide free electrical advice to both professional and DIY electricians. Whether seeking advice for auto electrics, trying to find electrical installation condition reports (EICR) form downloads, or whether you're here just to talk to other electricians; we've been a first-choice website for tens of thousands of sparkies for well over a decade.
Top