shed and rcd's

[paul b b]

hello chaps,

anther shed qusestion!!!!

ok, if the house has an rcd would you put a garage unit with rcd in aswell or just the main switch?

the said shed will be an office, but there is also a garage he wants power in, i have yet to see the job so dont know all of the details, its in the sticks so prob a TT on rewireables lol, may talk him into a cu change aswell

and whilst we are on it, would you use conduit?

thanks for the advice

paul

 

[Apache]

No need for more than 1 RCD. You could put shed on non RCD way and RCD in shed if you want to save a walk back to the house, or just put it on house CU's RCD and a main switch in shed.

I think conduit is a good idea. I have 90 meters of the stuff. I really hope it's a good idea

 

[paul b b]

thanks patch, i find having 2 rcd a pain when testing.

the problem being that unless the you can get the cable >50mm in a wall from the cu to outside you nee it to be on a rcd

 

[Apache]

thanks patch, i find having 2 rcd a pain when testing.the problem being that unless the you can get the cable >50mm in a wall from the cu to outside you nee it to be on a rcd

Run it in SWA!?

 

[paul b b]

ahh good point, i normaly run twin to cu for ease of temniating to out side then swa from there.

the question of exporting will nodoubt arise aswell lol

 

[Andy™]

thanks patch, i find having 2 rcd a pain when testing.

there is an easy solution... test between ingoing neutral and outgoing live of the RCD. it wont trip any other RCD's int he circuit

 

[paul b b]

[quote name='Andy

 

[Andy™]

ahhh thanks andy, so netral probe on incoming netral, live probe on outgoing live and earth crock clipped on to the met of the garage cu?thanks

no, earth & neutral both onto incoming neutral on RCD

the idea is you send the earth 'fault' current to neutral, instead of earth, so there is no imbalance other than RCD under test

 

[paul b b]

[quote name='Andy

 

[Andy™]

thanks andyso do this in the shed and all done, wish i knew this before could have save me running back and forth lol

do this on any RCD and it avoid anything else tripping

 

[M107]

If it's a TT supply at the house.

• Split tails at house or go non-rcd side of cu.
  
• Surface or conduit/trunk T/E from cu to enclosure, or use 25mm tails if splitting house supply tails.
  
• Install 100mA s Type rcd in enclosure (& mcb of corrcet rating for your design, if meter tails are split).
  
• Run swa as submain to shed.
  
• Use cu in shed with main switch & rcbo's or a 30mA rcd as main switch & mcb's.
  
• TT the shed.
  

or if house is pme export the pme.......me I lean towards TT'ing outbuildings, just personal prefrence.

If the shed is not being lined inside then yes I'd use conduit (would probably use it even if the shed was to be lined).

 

[ianmacd]

hello chaps,anther shed qusestion!!!!

ok, if the house has an rcd would you put a garage unit with rcd in aswell or just the main switch?

the said shed will be an office, but there is also a garage he wants power in, i have yet to see the job so dont know all of the details, its in the sticks so prob a TT on rewireables lol, may talk him into a cu change aswell

and whilst we are on it, would you use conduit?

thanks for the advice

paul

Do not forget about discrimination.

If it was me I would not want an RCD down the other end of the garden and defiantly not shared between other circuits.

If they want network around the shed too then I would look at fitting some large trunking (like this: http://www.tlc-direct.co.uk/Images/Products/size_3/UVSLCXX.JPG).

 

[paul b b]

thanks Mr 107

do you use the armour as earth or 3 core?

 

[Andy™]

armour is always earthed, but you can also use a core as the earth

most of the time, i use the armour as the earth

 

[paul b b]

thanks andy, last time i did one i used 3 core and connected the amour via a banjo, please dont tell me this is wrong.

 

[Andy™]

thanks andy, last time i did one i used 3 core and connected the amour via a banjo, please dont tell me this is wrong.

the armour must always be connected to earth at source. if using a core as earth, then the other end doesnt need armour connected to earth, but you may aswell. obviously, armour will need connected at both ends if using armour as the earth

 

[M107]

+1 with andy

If submain is a large/long one I go with 2 core & use armour as the cpc (so long as armour meets csa requirements) it keeps cable cost down.

Other wise use 3rd core as cpc & still connect armour the earth via banjo or earthnut (Q patch with link to picture of piranah earth nut).

 

[paul b b]

phew!

thanks again, done something right then.

if you use the amour, what to you put on the cert for the size of the cpc?

 

[M107]

[quote name='Andy

 

[Badger]

ive always tried to install shed greenhouse supplies, pond/waterfeature electrics on its own rcd so any problems done effect the rcd in the house and vise versa