Wiring for a compressor

[ban-all-sheds]

Putting aside the issue that the supply authority should be informed of a inductive load of this size on a domestic supply

Not an issue which can be ignored.

 

[ban-all-sheds]

While I am at it I might as well put an additional socket circuit in for my MIG welder!!

And apply for permission to use the welder as well.

It might be an idea for you to take a step back, draw up a list of everything you have, plan to have, or might have in the garage, and discuss the whole thing with your DNO.

 

[Adam_151]

How big can you go with a CU? Could I, for example, have 48 ways or is that just daft?
D

How big is your house? How big is your kitchen?

48 Ways might be just a little excessive for a large property with everything divided up into small circuits, it is completely draft for a 2 bedroom terraced house

I've got a 16Way board in the (attached) garage, feeding garage and most of the bungalow. I did have the intention to take everything back there, but then I thought about the circuits I would have to run back from the kitchen (opposite corner) and decided to put a second board in there for just the kitchen and (future) conservatory. Its a 14 way and didn't need to be that big but there was little difference on price or physical size, so got some spare ways there. Things have ended up with their own circuit simply because doing so fitted in with re-wiring as I go with decorating, and refurbising rooms etc

 

[dunny]

The house itself is pretty big but also it has 2 large outbuildings plus a couple of other outside brick buildings. I guess though these will have their own supply cables and CU's in time. I will need a fair amount of outside power in time too hence why I was thinking I would need a large CU. The kitchen is quite large and will have a largish utility room so I am thinking 48 ways might give me plenty of futureproofed growth capability. Trouble is I dont really know enough about how it would all be wired. In my last house I had an upstairs socket circuit, one downstairs, one for the kitchen, one for external and 3 lighting circuits plus boiler and shower and a couple of spares. House was probably half the size of this one with much less power requirements outside.

I guess for now I am overthinking it and should just sort out the garage!!

Thanks

D

 

[ban-all-sheds]

Give what you say about outbuildings and outside power I can't think of a fundamentally worse design than one giant CU for everything.

 

[dunny]

Give what you say about outbuildings and outside power I can't think of a fundamentally worse design than one giant CU for everything.

I meant that each building outside would have their own supply cable and CU (although I dont know how that would be achieved since it all has to be after the meter? The large CU would then do the whole house and outside.

I dont know enough to design any of this of course, just throwing ideas around so I can ask the spark what to do for the best. Wish one of you chaps were close!!

D

 

[333rocky333]

I meant that each building outside would have their own supply cable and CU (although I dont know how that would be achieved since it all has to be after the meter?

They would be called sub-mains and as you say all after the meter.
proberly from there own switchfuses (similar to what you have) near the meter or some people do feed them from a mcb in the main board, though thats more prone to unwanted tripping in fault conditions.
If theres a lot of outbuildings and a lot of switchfuses you could connect them all to whats known as a Bus Bar chamber.

 

[dunny]

I meant that each building outside would have their own supply cable and CU (although I dont know how that would be achieved since it all has to be after the meter?

If theres a lot of outbuildings and a lot of switchfuses you could connect them all to whats known as a Bus Bar chamber.

When I get the pole removed I will need to put in a new meter point on the external wall, could the bus bat chamber go in here?

Realise I am moving well off topic but its just that there will be changes and I want to do the right thing.

Thanks

D

 

[Echo the husky]

Bus Bar chamber.

Good grief! He's going to need to build a switch room at this rate!

 

[ban-all-sheds]

The large CU would then do the whole house and outside.

48 ways for the house and garden?

Is this your gaff?

 

[dunny]

Ah...I assume this is a big thing then!!

As I said I am over thinking this.....get the spark in next I think!!

D

 

[dunny]

The large CU would then do the whole house and outside.

48 ways for the house and garden?

Is this your gaff?

Spooky........how did you guess??

 

[DaveHerns]

Has Her Maj had her home rewired yet ? I heard the wiring was in a terrible state

 

[ericmark]

I was involved in the conversion of a mill to a house and we wondered about the supply required for such a large property. We fitted a 160A three phase fused isolator linked all phases together fitted 60A fuses and fed three consumer units placed in different areas of the property with the idea if in the future it was found 100A feed was not enough we could either up to 160A or use three phase. As it transpired it was not required 100A was ample.

Farms often have split phase supplies 230 - 0 - 230 where as commercial premises in towns have three phase supply. Using a compressor or the size you have and mig welders it must be considered as commercial premises with an attached residential area and step one is to talk to DNO about what supply is available.

A consumer unit is normally limited to 100A I seem to remember the type testing spec does allow 140A but personally never seen a consumer unit over 100A. As we move to split and three phase we use distribution units these may not be type tested and as such can't be under the control of an ordinary person, it needs an instructed or skilled person. As a result in the main the supply goes to an outbuilding which is commercial then from outbuilding to farm house so the farm house only has a consumer unit.

BS7671 is not law although it can be used in a court of law, so the building inspector has some lea way and can allow things which don't comply with BS7671. But members of schemes agree to abide with BS7671 so as far as they go BS7671 is law.

All the new circuits will come under Part P in England and Wales so in the main we would use a scheme member who can self certify rather than pay LABC fees.

You as it stands can only have a 100A supply and it does not matter how many ways you have in the consumer unit that's all you can have. This is well past DIY stage your doing commercial type work so you need to select an electrician and get him to advise and to enquire as to supply available this should have been done before you got the compressor really. You need some one with both domestic and commercial experience. Today Part P has resulted in sole traders going for one or the other as scheme membership fees are too large to pay if not doing near all domestic. So either an old guy or a firm with many electricians.

But really the person sorting it out needs to be there. This is not something which can be sorted out on a forum, the person needs to be on site and see what you have got. One guy I know uses a generator for his workshop he does not use the workshop enough to be worth getting a supply put in lights only from house. He bought the generator cheap and he lives in the middle of nowhere. Think it's Ex GPO?

 

[ban-all-sheds]

All the new circuits will come under Part P in England and Wales

Not just new circuits - Part P applies to any work whatsoever on fixed electrical cables or fixed electrical equipment located on the consumer’s side of the electricity supply meter which operate at low or extra-low voltage and are—
(a) in or attached to a dwelling;
(b) in the common parts of a building serving one or more dwellings, but excluding power supplies to lifts;
(c) in a building that receives its electricity from a source located within or shared with a dwelling; or
(d) in a garden or in or on land associated with a building where the electricity is from a source located within or shared with a dwelling.

Today Part P has resulted in sole traders going for one or the other as scheme membership fees are too large to pay if not doing near all domestic.

This is Part P:

It says nothing about scheme membership.