Pat testing cable size

[contender1]

Hi Guys

I've just had a discussion with my boss about cable sizes when pat tesing 415v equipment.

This is how i have been dealing with cable sizes.

If i have an extension lead with 32A plugs and sockets on I always make sure it has a minimum of 4mm cable so that it is capable of carrying the full load current of 32A as i have no idea of what equipment will be plugged into the extension lead.

On the other hand if i have a new piece of equipment delivered to the factory it may have 2.5mm cable, 32A plug, but the rating plate states the device only draws 10A for instance. Providing all other checks are ok I would pass this equipment. As i know that the cable is capable of carrying the load as i know what is fitted to it.

Now my boss had a welder delivered recently which had 2.5mm cable and the rating plate stated it draws 10A. He wouldn't fit a 32A plug on it as the the cable would be underrated for the supply it was being plugged into and under fault conditions the cable could draw more current than the cable was intended to carry and could catch fire. So what he did was fit a 16A plug. He then made a made a portable box with a 16A mcb fitted. This box was then fitted in between the 32 mains socket and the device.

Now I understand why he did this but as the main pat tester I'm now unsure of where my responsibilities end.

Should i pass equipment with 2.5mm cable and 32A plugs.

We dont have 16A sockets on the shop floor at the moment so fitting 16A plugs isn't an option at the moment.

Cheers
Nick

 

[Pete999]

Nick, Do you have a copy of the CoP for ISITEE (PATesting) as it was? you should find all your answers in the CoP.

 

[contender1]

Yes i do have a copy, I did scan through and couldn't find the answer.
Maybe i should have a sit down and have a thorough look.

 

[Pete999]

Yes i do have a copy, I did scan through and couldn't find the answer.
Maybe i should have a sit down and have a thorough look.

Good idea

 

[contender1]

LOL

I'll re check but I'm not convinced I'm going to find the answer.

With single phase equipment you often have cable lower diameter cable than the 13A socket but then its covered by the fuse I guess.

Pat testing 3 phase seems a bit more of a grey area to me

 

[contender1]

Right I've just rechecked the cop and gone right through the contents list and I can't find any reference to my problem.

Are there any other pat testers on here who test industrial machinery that could point me in the right direction please.

 

[westward10]

You can consider the appliance rating in regards to cable csa. For a 32A extension lead I would however suggest the cable should be rated at 32A.

 

[contender1]

Ok so you basically do the same as me.

What about the plug, would you be happy to fit a 32A plug, providing the csa of the cable is large enough to carry the design current of the appliance, but not necessarily 32A.

 

[westward10]

Yes, the appliance may also have internal circuit protection.

 

[sham]

My thoughts are you are doing a pat test of the portable appliance only. I have basic knowledge but I just feel that everything else is not your concern. Been on many jobs and an 32A plug is connected to an 2.5 but the mcb is 16. An 13A, 3 pin plug does not have to have a 13A fuse.

 

[Taylortwocities]

An 13A, 3 pin plug does not have to have a 13A fuse.

It depends on the plug. A BS1363 plug MUST have a suitable fuse no greater than 13A

 

[Deleted member 105166]

If i have an extension lead with 32A plugs and sockets on I always make sure it has a minimum of 4mm cable so that it is capable of carrying the full load current of 32A as i have no idea of what equipment will be plugged into the extension lead.

For flexible cables, you need to refer to Table VI.1 on page 134 of the ISITEE book. 4mm2 cable in rated to 25A, not 32A.

He then made a made a portable box with a 16A mcb fitted. This box was then fitted in between the 32 mains socket and the device.

What's on the end of the MCB - a 16a or 32a socket I presume?

Now I understand why he did this but as the main pat tester I'm now unsure of where my responsibilities end.

It looks like you have a portable distro - inspect and test it in the same way you would a Rubber Box type distro.

LOL
Pat testing 3 phase seems a bit more of a grey area to me

When testing three phase extension leads, make sure you do proper insulation tests between the cores. Those IEC60309 "PAT adaptors" with the phases commoned are OK for the earth continuity test, but not for the insulation resistance test. Any breakdown in insulation between the three lines would go undetected, unless they are tested separately.

 

[westward10]

When testing three phase extension leads, make sure you do proper insulation tests between the cores. Those IEC60309 "PAT adaptors" with the phases commoned are OK for the earth continuity test, but not for the insulation resistance test. Any breakdown in insulation between the three lines would go undetected, unless they are tested separately.[/QUOTE]
A PATester does not IR test between line/neutral anyway as the tester internally links these two and tests to earth only. This would be the same scenario for multi phase equipment when using an adaptor.

 

[Deleted member 105166]

A PATester does not IR test between line/neutral anyway as the tester internally links these two and tests to earth only. This would be the same scenario for multi phase equipment when using an adaptor.

For three phase extension leads, an MFT instead of a PAT instrument should be used.