over current protection to compressor

[blue eyes]

hi all

I have a 3phase compressor to wire. there is a spare 3phase way available 20A.
The compressor in ratedat 10A. Now I an of the feeling that the MCB is to protect the cable which will be 2.5mm swa (and not the compressor which should have itown mean of protection)


this is a commercial property with type C breakers But I have searched all local wholesalers and the MCB are so old I can not get one.


The compressor is to beplaced inside a metal storage cabin which has power light supplied bya T.T supply.
I am a bit concernedthet there may be a problem in introducing a compressor supplied by aTN-C-S supply

cheers Blue eyes

 

[blue eyes]

any comments please

 

[Bobster]

An overload?

 

[blue eyes]

An overload?

as it is a fixed load in theory no over load protection is needed.

 

[blue eyes]

can any body coment on this.

 

[Knobhead]

Overload, as in motor protection overload relay!

You haven't told us the size of the motor so how is anyone supposed to help!

As for TT have you even thought how compressed air is piped?

 

[malcolmsanford]

hi all

I have a 3phase compressor to wire. there is a spare 3phase way available 20A.
The compressor in ratedat 10A. Now I an of the feeling that the MCB is to protect the cable which will be 2.5mm swa (and not the compressor which should have itown mean of protection) Yes the MCB is to protect the cable, the compressor if over 0.37kw will have an overload built into it's control system.


this is a commercial property with type C breakers But I have searched all local wholesalers and the MCB are so old I can not get one. Then you need to design a different approach to this then


The compressor is to beplaced inside a metal storage cabin which has power light supplied bya T.T supply.
I am a bit concernedthet there may be a problem in introducing a compressor supplied by aTN-C-S supply There are several options here available but it depends on enviroment, such as is the site Agricultural etc.
Why was the cabin made TT?
Where does the supply for the cabin lights come from?
You could tie the TT rod to the TNC-S system if allowed. You could make your supply to the compressor a sub main, protecting the sub main by TNC-S and then divorce it from the TT system and have the compressor on TT.
Really need more info

cheers Blue eyes

.........................