32A Industrial Socket Cable Question

[PerpetualLeakingRoof]

Hi, I have a CU in the workshop and would like to fit a new radial circuit for a 32A industrial socket (an MK Commando) to run a welder with a maximum draw of 20A. I plan on fitting a 32A Type C MCB in the CU. This is only a short term installation (until the new workshop is built, ) so the cable will be clipped directly to the wall and the run will be less than 2m.

Given these conditions I think I should be able to get away with a 4mm cable, is that correct? Ideally though I'll like to use 6mm to be on the safe side but I'm really struggling to find anywhere that sells 6mm flex. I can't see standard T&E maintaining the IP rating on this socket is it wouldn't seal correctly around the cable entry. If someone could point me in the direction of appropriate cable that would be greatly appreciated.

Is there anything else I should consider?

Cheers

 

[Chri5]

SY?

NYY?

http://www.tlc-direct.co.uk/Products/NY6slash3.html

 

[PerpetualLeakingRoof]

Thanks, I checked TLC last night, must have had my eyes closed.

I think I'll go with the NYY, the SY looks over kill for what I currently need.

 

[JohnW2]

I can't see standard T&E maintaining the IP rating on this socket is it wouldn't seal correctly around the cable entry.

You're right in terms of standard cable glands, but they've thought about that one - see here. Those ones may well not be usable for 4mm²/6mm² cables (although you might be able to use them for 4mm² T+E, which isn't that much bigger than 2.5mm²), but, if you look around, the same concept may exist for larger cables.

Kind Regards, John

 

[Robin0577]

We carry 4mm, 6mm and 10mm H07-RN-F rubber flex in stock where I work and glands to suit, as do most theatre lighting & entertainment industry suppliers. "Commando" or "Ceeform" type plugs and extensions are the norm in our industry. Would that suit your application?

PM me if you require a link

 

[plugwash]

This may sound like a silly question but what IP rating do you actually need to maintain? is this socket going to be outdoors?

 

[PerpetualLeakingRoof]

The socket will be installed in a indoor workshop. It's damp at the moment because there is a leak in the roof (no where near any electrics). Strictly speaking I don't suppose I need to maintain the IP rating as it's not terribly dusty and there shouldn't be any water, let alone splashing water, about but if I can maintain it I would like to.

@robin, cheers, I'll have a look around for that.

 

[Iggifer]

second vote for H07-RN-F, great flex

 

[ricicle]

What protection do you have at the source to feed the workshop DB ?

 

[PerpetualLeakingRoof]

The workshop cu is connected back to the main house cu via a 10mm t&e, part of the run is in trunking the rest under a floor in free air, and is on a 50A type b mcb which is protected by an rcd.

I don't have the figures to hand right now but I remember zs was very low so I think I should be ok with a type c.

 

[ricicle]

The 50A type B at the origin might not necessarily take the inrush of a welder requiring a 32A circuit.

 

[PerpetualLeakingRoof]

Yes, I was wondering if it would take it without tripping. The welder actually has a maximum draw of only 20A and I'll not be running it flat out any time soon so I'm hoping it'll work till the new shop is built.

 

[Iggifer]

What's the 'amp rating' of the welder?

I have a 160a cheapo arc welder that would trip a B16 but not a C16 on the inrush, but it wouldn't do it every time, so must be right on the trip curve of a B16

 

[PerpetualLeakingRoof]

It's 200A in MIG mode. I have a 16A socket already, as I don't need full power on the welder I considered running it on that for now but I've bought the 32A socket so I might as well do the job properly now.

 

[Iggifer]

I think, if it was me, I would go ahead as planned, and then if you get nuisance tripping on the B50 swap it out for a C50 (if you can get them for your board) but I think you'll be ok on a B50