Single phase contactor

[daza1001]

Hello All,

Today i am connecting up a single phase contactor.
I know the contactor needs a neutral to operate the coil, but does the neutral for the load have to run through the contactor as well? As you can tell I have not done to many of these.
The contactor is for the underfloor heating as it is drawing 19.5A & the programer is rated at 16A.

Many thanks

 

[daza1001]

Sorry, I know normally the neutral does run through the contactor, but i was just wondering if it had too.

 

[ashrow]

if the programmer is rated at 16 amp then no more the 16amp should be switched via that programmer
You could use the programmer to switch contactor which would then switch the required load
I always switch my live and neutral via the contactor ie 2 pole or 4 pole depending on number of phases

 

[daza1001]

Hello Ashrow,

That is what we have done. But a mistake was made when the cables were 1st fixed & 1 cable less was pulled from the programer to the contactor than required.
So I was hoping we could do away with running the load neutral through the contactor that then gives us enough cable cores.

Hope this makes sense.

 

[ashrow]

I cant think of a reg that says you can not do what you ask
The more learned members here may give better advise

 

[davelerave]

if the programmer is rated at 16 amp then no more the 16amp should be switched via that programmer
You could use the programmer to switch contactor which would then switch the required load
I always switch my live and neutral via the contactor ie 2 pole or 4 pole depending on number of phases

i wouldn't switch the 3P and N through a 4-pole
i'd use a solid link for N myself

 

[telectrix]

it is always a good practice to switch both line and neutral through the contactor. but if you can't do it, then just switching the line will be acceptable. just as an afterthought..... you have a N for the coil. can you not use this to feed a N pole on the contactor?

 

[daza1001]

Telectrix,

If I used the neutral from the coil cct this has been fused down to 13A so would this still work?

Thanks

 

[Knobhead]

With a single-phase load break the line only. What are you talking about? 13A fuse for neutral?

 

[telectrix]

Telectrix,

If I used the neutral from the coil cct this has been fused down to 13A so would this still work?

Thanks

the N is not fused down, as tony pointed out. all down to if the N cable is of sufficient size to carry the 19.5A (+ a little bit for the coil).

 

[daza1001]

Sorry, I meant the live had been fused down.