Kiln cable size

[Taylortwocities]

Hello again

I'm about to install this kiln (with help from an electrician). I need to buy a suitable isolator to fit adjacent to the kiln. I was looking at this:

http://www.toolstation.com/shop/Ele...essories/sd3080/Rotary+Isolator+4+Pole/p70254

but I notice that though 63A it's only 30 kW, and my kiln is 47.7 kW. I assume therefore that it's not suitable. It's the biggest that Toolstation do. Could someone kindly point me to what I need?

Thanks
Richard

You need to have a serious look at your requirements then. I suggest talk to your electrician. 47KW??? are you sure????

47KW is more than 200amps and that is twice as much as the feed into your house……….!!!!!

EDIT. I dont want to read back over a hundred posts, but I rather think that you meant 47.7AMPS
If so, when i went to school, 47.7 was smaller than 63, so the Toolstation isolator would be OK.

 

[geraldthehamster]

Thanks, I'm a complete idiot. I was up early this morning and was not thinking straight.

Cheers
Richard

 

[JohnW2]

EDIT. I dont want to read back over a hundred posts, but I rather think that you meant 47.7AMPS ... If so, when i went to school, 47.7 was smaller than 63, so the Toolstation isolator would be OK.

That is, indeed, what the very first post in this thread said. However, it also said 10.5kW, implying that the 47.7A related to 220V. The current at 230V is therefore probably somewhere around 50A, but still fine on a 63A isolator (although the OP does not need a 4-pole one).

Kind Regards, John

 

[geraldthehamster]

The current at 230V is therefore probably somewhere around 50A, but still fine on a 63A isolator (although the OP does not need a 4-pole one).

Kind Regards, John

Thanks John. The only reason I was looking at the 4 pole one is that I have an account at Toolstation and they have the rest of the stuff I need. The only isolator they have of that capacity is 4 pole.

Cheers
Richard

 

[JohnW2]

The current at 230V is therefore probably somewhere around 50A, but still fine on a 63A isolator (although the OP does not need a 4-pole one).

Thanks John. The only reason I was looking at the 4 pole one is that I have an account at Toolstation and they have the rest of the stuff I need. The only isolator they have of that capacity is 4 pole.

Fair enough. Yes, I looked around Toolstation and they didn't seem to have any suitable 2-pole ones. There's obviously no problem in using a 4-pole one - you just ignore two of the poles.

Kind Regards, John

 

[ban-all-sheds]

Yeah, but even without looking for cheaper suppliers, let alone on eBay..

http://uk.rs-online.com/web/p/produ...lex|Consumer+Units-_-569685&kpid=&kpid=569685

 

[geraldthehamster]

That's a pint I owe you, I think



Cheers
Richard

 

[geraldthehamster]

Can someone tell me please, is there any reason to use the larger rotary 63A isolator, rather than the little, less expensive 110A switch ?

Cheers
Richard

 

[JohnW2]

Can someone tell me please, is there any reason to use the larger rotary 63A isolator, rather than the little, less expensive 110A switch ?

I guess that's a matter of opinion. Those 'little less expensive 100A switches' are usually used (e.g. in consumer units) as isolators that get switched on-off once in a blue moon, rather than being constantly switched on and off. I don't know how well they would fare in the latter situation but I would personally be hesitant to use them in 'frequently' operated' situations. They are also pretty 'stiff' to operate. However, others will undoubtedly disagree with me!

Kind Regards, John

 

[geraldthehamster]

Thanks. Good point.

 

[Jackrae]

If you want to frequently break the electrical circuit whilst it's under load you might be better incorporating a contactor into your system. Some isolators have rated current carrying capacity which might not be the same as current breaking capacity under repeated operation.

 

[EFLImpudence]

In view of what seems to be available - and the prices - I think the OP's choice is sensible (assuming it is not cheap because of low quality).

Although you will have two spare contacts if it wears out.



With regard to contactors (and prices), what about a 63A RCD?
Press button to turn off.

I'll get me coat.

 

[geraldthehamster]

If you want to frequently break the electrical circuit whilst it's under load you might be better incorporating a contactor into your system. Some isolators have rated current carrying capacity which might not be the same as current breaking capacity under repeated operation.

It wouldn't be broken while under load. It would only be switched off when a firing had finished and the kiln was not in use. Really it's mainly a way to connect the incoming 10mm cable to the cable attached to the kiln, and it made sense to do this by means of an isolator - not that I have kids who might otherwise be tempted to operate it.

Cheers
Richard

 

[EFLImpudence]

50A cooker switch, then.

 

[geraldthehamster]

50A cooker switch, then.

Aren't they designed for 6mm cables?

Cheers
Richard