Been out of electrical for a while and suprising what you forget

[junior-sparky]

Hello All,

Ive not been into electrics for almost a year due to ill health and now I'm back together I'm getting back on it and getting my hands dirty. Sorting out all My Part-P etc and you forget the simplest thing.

My first job is my new house is having a new office/garage built for the wife!

hopefully the picture attached is better than my desription.

1) CU in house will be upgraded to a 3 way for my Part-P inspection also to have the swa from the house to the office.

2) SWA will be 4mm which I'm told by the catalouge is rated to 42amps at a length of 15 meters.

3) SWA will be on a 20A mcb from house to office with a garage CU other end which will be main switch, 30ma rcd 1x 6A mcb for 1 LED lamp and 2 strip lights and 2 x 6-10A mcb for 4 sockets on each of those.


The office is only being used for a computer maybe a small heater and the occasional lawnmower, she might even have a radio or tv.

All opinions welcome as I'm sure I've over or not thought something correctly.

 

[Leesparkykent]

when you say board will be a 3way...do you mean high integrity?

 

[junior-sparky]

Garage/ normal consumer unit / high integrity board.

 

[uksparks]

I was just wondering that.

 

[Leesparkykent]

any extraneous conductive parts within garage/office?

 

[junior-sparky]

Good spot, no extraneous parts at all.

 

[Leesparkykent]

are you putting the mcb for the garage supply on the mainswitch side of the high integrity board in the house?

 

[junior-sparky]

In the house the MCB will be on the main switch side (separate from house RCDs)

 

[Leesparkykent]

In the house the MCB will be on the main switch side (separate from house RCDs)

looks good then(as long as the house isn't TT) apart from the sockets being on a 6-10A mcb

 

[junior-sparky]

Only reason I chose that amapage is because there wont be much power going through them for the computer but actually thinking about it she might have a heater 2kw pulling in 8 amps alone!! What Would you put them on considering its a 20a MCB feeding it 16??

 

[Leesparkykent]

Only reason I chose that amapage is because there wont be much power going through them for the computer but actually thinking about it she might have a heater 2kw pulling in 8 amps alone!! What Would you put them on considering its a 20a MCB feeding it 16??

yeah a 16A or 20A. Most garage boards come supplied with a 6A and a 16A mcb anyway so may as well use them.

 

[junior-sparky]

Thank you very much for your help . can sleep happy knowing its still in there somewhere

 

[telectrix]

for the difference in price, use 6mm SWA on a 40A MCB. this will allow for future additions which, i'm sure, are inevitable where a woman is concerned.

 

[Plonker 3]

Hello All,

Ive not been into electrics for almost a year due to ill health and now I'm back together I'm getting back on it and getting my hands dirty. Sorting out all My Part-P etc and you forget the simplest thing.

My first job is my new house is having a new office/garage built for the wife!

hopefully the picture attached is better than my desription.

1) CU in house will be upgraded to a 3 way for my Part-P inspection also to have the swa from the house to the office.

2) SWA will be 4mm which I'm told by the catalouge is rated to 42amps at a length of 15 meters.

3) SWA will be on a 20A mcb from house to office with a garage CU other end which will be main switch, 30ma rcd 1x 6A mcb for 1 LED lamp and 2 strip lights and 2 x 6-10A mcb for 4 sockets on each of those.


The office is only being used for a computer maybe a small heater and the occasional lawnmower, she might even have a radio or tv.

All opinions welcome as I'm sure I've over or not thought something correctly.

View attachment 30560

There a little bit more to electrical science than reading what it says in a catalogue. You need to do your calcs yourself rather than what that tells you.

 

[Midwest]

You could consider using RCBO's in the garage/office CU instead of a single RCD. Pricey, but does better division of circuits.