RCD question

[sammysnail]

hello all

i'm new so take it easy on me

it may seem a silly question but i'm a maintenance electrician and have been asked to install a 3 phase rccb in its own enclosure for a welder supply. The rccb is a merlin gerin 4 pole but there are no wiring details for it - do the supply cables go in the top and load in the bottom or vise versa? it is marked n-1-3-5on the top and n 2- 4-6 on the bottom and is this generally the same for all rccb's

thanks

 

[Evans Electric]

I would say either way , the n must be neutral. Puzzled as why you want one on a welder TBH

 

[sparkytim]

Hi

Yes normally 4 cores in at top and out at bottom, but can be other way round and it will still work ok.

 

[sammysnail]

I would say either way , the n must be neutral. Puzzled as why you want one on a welder TBH

thanks for this - the welding is on the roof in a welders tent and health and safety dept have insisted on it being rcd protected

 

[Evans Electric]

My immediate thought is that it will keep tripping but I suppose the primary side is clean . Just never seen an RCCD on a welder.

 

[sammysnail]

just of interest would a 4 pole mccb work either way round?

 

[Evans Electric]

Yes , almost all RCCDs can be connected either way . Surprised that the welder needs a neutral, though . Most I've come across are 2 phase only.

 

[steptoe]

if you look on the side of the RCCB you may see an internal connection diagram,

although it should work either way there is a way normally it should be wired,

ie, so the power is disconnected before the coil.

HTH.

though probably not much.

 

[Andy™]

just of interest would a 4 pole mccb work either way round?

MCB's should work either way