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.

 

[ruston]

And if your wife is the main occupant, consider an emergency light so she is not sitting in the dark if the rcd trips.
15 meters in the black dark is a long way, unless she is well trained at resetting it.

 

[LankyWill]

whats a high integrity board?

 

[Leesparkykent]

whats a high integrity board?

It's a consumer unit with 3 neutral bars. Each RCD has a neutral bar and a neutral bar for circuits that you want to put on the main switch side before the RCD's. Comes in Handy for circuits that don't require RCD protection or if you want to put a particular circuit on its own RCBO.

 

[pennychew]

whats a high integrity board?

It won't kiss and tell