Repositioning CU

[Midwest]

I have a friend ..............seriously, I'm will retrain as an electrician next year when I retire, and a work colleague has asked some advice.
He is planning a kitchen extension. Currently his CU is installed in an integral garage and if anything trips, they have to go outside to go in the garage to reset. Not very convenient in the middle of winter. So he is planning to have a new CU installed in the extension at the other side of the house. His problem is the meter/supply will still be in the garage.

•He is thinking of getting the meter/supply moved - prohibitively expensive I would have thought.
•Having an internal door installed in the garage & leaving the CU where it is, but having an impact on the room where the new door is installed

I'm thinking he could supply the new CU with a SWA and replace the old CU with an isolator to terminate the SWA to the old meter tails. Am I right in thinking this would comply with 7671 and that the SWA would not need an RCD (defeating the whole object of moving the CU)? A cheaper option to the above.

 

[telectrix]

if the SWA is more than 3m in length, a switched fuse is required, not just an isolator. if the DNO fuse is 100A, then your sw . fuse should be 80A.

 

[KINKY]

How often does he have to go outside into the garage to reset an MCB/RCD.

Is he having to reset MCBs that often to make it worth while moving the CU?

 

[Midwest]

Ok thanks. Then his CU isolator would need to be 80A, so he needs to be careful in terms of loading on his CU (not sure what he has in terms of cooker circuits, electric showers etc), but the idea is okay.

 

[Midwest]

How often does he have to go outside into the garage to reset an MCB/RCD.

Is he having to reset MCBs that often to make it worth while moving the CU?

He works shifts, and doesn't like the idea of his wife going at out night to reset trips.

 

[Guest55]

Fitting an internal door would be easier / cheaper than moving the CU to the other side of the house.

 

[Midwest]

Fitting an internal door would be easier / cheaper than moving the CU to the other side of the house.

True, guess he needs to get a quote off the builder and electrician. But it still isn't ideal cos there'll be a car to negotiate around a two switch to install and getting past his wife the idea of a door in her dining room. I'd go for the CU move. Thanks for your advice guys.

 

[snowhead]

I'd be tempted to find out what's causing the tripping first.

Life was so much easier pre RCD RCBO, it was just stepping over all the dead bodies caused by electrocution that used to be a bit inconvenient..

 

[Midwest]

I'd be tempted to find out what's causing the tripping first.

[/QUOTE

Just normal mcb trips for blown GU bulbs etc. Still pain in the bum going outside on a cold rainy night in December I guess.

 

[Guitarist]

If he is planning to move his CU to the other side of the house, not only will he have the Switchfuse to buy and install, but the swa you mentioned, along with moving/extending every cable in the house into the extension loft and down. This is a massive project for the small gain he will achieve. If it is just lamps blowing which is the trip problem then he could :-

a) Change the GU lamps for LED types.

b) Change the fittings altogether.


My advice would be to sort the lighting out or cut a fire-door in to the garage as already stated.

 

[Midwest]

Okay I will pass on your advice.

 

[Adam W]

Firstly I'd get an electrician to investigate why the breakers are tripping; if it's because of conditions in the garage obviously moving the CU is the way to go, otherwise I'd go for the door option so this woman (I didn't understand the background of it at all - the first paragraph made no sense at all) can access other things in the garage as well as the consumer unit, without going outside.
Presumably there is already at least one door in the dining room otherwise nobody would be able to get in or out.

Is this actually a real problem or is this guy just playing devil's advocate?

 

[Des 56]

Ok thanks. Then his CU isolator would need to be 80A, so he needs to be careful in terms of loading on his CU (not sure what he has in terms of cooker circuits, electric showers etc), but the idea is okay.

You mean the fuse has to be 80 amp
But there again,is that necessary ?

Anyone like to explain or tell me where it states there is need for discrimination with the suppliers fuse ?
You size the fuse to suit your own installation,the Dno fuse is a supply capacity issue

 

[Geordie Spark]

He works shifts, and doesn't like the idea of his wife going at out night to reset trips.

That's one of the things we Geordies keep wives for. :smilielol5:

 

[J&M Electrical]

We had the same potential issue on a recent new build. The consumer unit was spec'd to go in the garage backing onto the meter cupboard, but no internal door from the house to the garage, so we moved the board slap bang into the centre of the property and used a 16mm 3 core SWA back to the meter cupboard.