2nd consumer unit

[adamjseed]

I have a standard consumer unit which is full and would like to expand it to accommodate some outside lighting and power. Ideally I would like a second consumer unit mounted a distance away from the primary one. I’m not an electrician but want to plan and do most of the leg work. While Ill get an electrician to connect up the bits I can’t, I have a few questions if anyone could help me out?

1) Ideally I want this unit to be a totally seperate unit. e.g. come from the mains electrics and not piggyback off the first unit.

2) If 1) is possible how far can it be away from the main supply?

3) are there any other considerations with 1)?

4) Can the second consumer unit be placed outside in an IP65 rated enclosure?

 

[riveralt]

I have a standard consumer unit which is full and would like to expand it to accommodate some outside lighting and power. Ideally I would like a second consumer unit mounted a distance away from the primary one. I’m not an electrician but want to plan and do most of the leg work. While Ill get an electrician to connect up the bits I can’t.

If you are not an electrician who is a member of the competent persons scheme you (he) cannot legally do any of the work you have suggested.

 

[flyingsparks]

Your electrician will be able to answer questions 1-4.

 

[adamjseed]

No, I'm not an electrician and like I mentioned, would not do the connections myself. Im wanting to know the above information to choose a site for my second consumer unit and to plan the underground wire location. 90% of the work will be digging trenches and that is what I'm planning for.

 

[dmxr]

Yes,Henley blocks & Switch fuse at main incoming supply, SWA from SwFse to DB2 mounted inside enclosure.

Get an Electrician in!

 

[westie101]

As post above, maximum tail length is 3m

 

[adamjseed]

Ok the Henley block looks good, and 3m length. What about mounting the 2nd consumer unit on the outside of the house?

 

[riveralt]

What about mounting the 2nd consumer unit on the outside of the house?

You can't do that.

 

[dmxr]

As long as it is in a suitably rated enclosure sheltered from environmental influences then there is no problem. Your electrician will run through all of this with you.

 

[OwainDIYer]

If you are not an electrician who is a member of the competent persons scheme you (he) cannot legally do any of the work you have suggested.

Why not? The work might be notifiable under Building Regulations, but that doesn't require it to be done by a qualified or competent person.

 

[deadshort]

I have a standard consumer unit which is full and would like to expand it to accommodate some outside lighting and power. Ideally I would like a second consumer unit mounted a distance away from the primary one. I’m not an electrician but want to plan and do most of the leg work. While Ill get an electrician to connect up the bits I can’t, I have a few questions if anyone could help me out?

1) Ideally I want this unit to be a totally seperate unit. e.g. come from the mains electrics and not piggyback off the first unit.

2) If 1) is possible how far can it be away from the main supply?

3) are there any other considerations with 1)?

4) Can the second consumer unit be placed outside in an IP65 rated enclosure?

Hi, it would perhaps be helpful if we knew how much lighting and power your addition CU would be required to supply?

Regards,

DS

 

[riveralt]

If you are not an electrician who is a member of the competent persons scheme you (he) cannot legally do any of the work you have suggested.

Why not? The work might be notifiable under Building Regulations, but that doesn't require it to be done by a qualified or competent person.

Oh Okay then.

 

[adamjseed]

wow it looks like there is a lot of different opinions. To be honest, this is why I posted on here as I have had a difference in opinion between two qualified electricians. I have a good knowledge of electrics, I even put a new ring main in a while back, but im unsure of a few finer points. I guess the main thing is to stick to building regulations.

 

[AndyPRK]

Without knowing what the load is, what you are suggesting could be way over the top in terms of large items and cost.

 

[ericmark]

Consumer Unit is a type tested distribution unit designed for domestic supplies. Although you can buy a WMDU (Weatherproof Main Distribution Unit) which are used exposed to the elements it would not be classed as a consumer unit as it would not have the type testing.

As to using a non type tested distribution unit in a domestic property I don't know of any rules which say you can't, but it would likely be missing the guards and isolation methods used in a consumer unit, and so would need some method of isolation. You are entering some grey areas and it would be hard to say what would be permitted. 530.3.4 states that BS EN 60439-3 is required for use by an ordinary person. Reading manufacturers data it would seem that covers more than the domestic consumer unit.

Running surface cables or using one of the list BS 5467, BS 6346. BS 6724, BS 7846, BS EN 60702-1 or BS 8436, then yes you could exceed the 3 meters, and I have seem many domestic premises when the consumer unit is some distance from the DNO equipment common in flats, but in the main we tend to feed the second consumer unit from the first using for example a 50A MCB.

There is a problem with a second consumer unit in that fire men may think a house is isolated when it's not so unless next to each other it would be normal to have a common isolator. Also there are some special rules for farm wiring an 1850's farm house is not what springs to mind when most are giving advice.

Consumer units are normally rated 100A and as a result the DNO fuse is also 100A maximum although could be as low as 60A, but in farms split phase is not unusual so I would suggest you get an electrician to give some advice on site, and then maybe if you want ask here once you have some ideas relating to your special circumstances.