UK 6KVA APC UPS installation

[helijimbo]

Hi all,

I've just installed an APC 6KVA SRT6KRMXLI.

As a computer network engineer and electrician, I was a bit baffled by the 35mm gland that came with this.

The hole in the gland is so large that your 4mm2 3-core flex that's standard on Comnando leads is not even close enough to go filling the gap in this gland. Luckily there was another gland on the cable that would fit in the other gland.

At 6KVA, that's under 32 amps, so anything larger than 4mm2 is unecessary for the commando plug to the UPS which is hard wired.

Am I missing something or have APC just made this really awkward to use the parts they supplied?

Looking at the specs they want 10mm2 cable which is absolute overkill but I know we also need to follow manufacturers instructions.

I'd like to add the 32A Commando socket was already in place.

What are people's thoughts on this?

James

 

[James]

So if they recommend a 50A 2 pole breaker it would be a good idea to ensure the cable is big enough to handle a fault that will trip the breaker.

 

[helijimbo]

So if they recommend a 50A 2 pole breaker it would be a good idea to ensure the cable is big enough to handle a fault that will trip the breaker.

Hi James, I agree with you, but the 32A Commando was already there, and within spec of the device.

So I'm toying with it's certainly OK because it's within spec of the device but the manufacturer recommends going overkill.

It does say, 'typical', for breaker and wire size.

I'm doing this job as part of my network engineer job and trying to use my electrician's hat to make sure I've done it properly.

 

[James]

In my experience of ups devices, they often have a huge inrush current when switching on or returning to grid from test.
a 32A breaker is likley to give you trouble with nusiance tripping.
therefore,the 32A commando socket is probably not going to be the right thing to be using.

you can throw all sorts of information in the air but really what you should be concentreating on are the manufacturers instructions .

 

[helijimbo]

In my experience of ups devices, they often have a huge inrush current when switching on or returning to grid from test.
a 32A breaker is likley to give you trouble with nusiance tripping.
therefore,the 32A commando socket is probably not going to be the right thing to be using.

you can throw all sorts of information in the air but really what you should be concentreating on are the manufacturers instructions .

I agree with you, and that's why I threw this out there.

Thanks James.