Steel Container/cabin with PME supply

[Aaron b]

Hello, Where I work there's a steel cabin that other employees have installed and powered up without certification. Am I correct in thinking it's covered under part 717.411.4 that it can not be connected to a PME supply? I've been asked to test it and I'm concerned with the design and installation of the supply. With how easy it would be to TT I don't feel the risk is worth it even if it wasn't covered by 717.

 

[timhoward]

Do either of the exceptions in 717.414.4 apply - is it under continuously supervised by skilled or instructed person(s), and was the earthing checked before it was connected. (You said it wasn't certificated; was it tested?)

 

[buzzlightyear]

Hello, Where I work there's a steel cabin that other employees have installed and powered up without certification. Am I correct in thinking it's covered under part 717.411.4 that it can not be connected to a PME supply? I've been asked to test it and I'm concerned with the design and installation of the supply. With how easy it would be to TT I don't feel the risk is worth it even if it wasn't covered by 717

what where they thinking faraday cage .

 

[cliffed]

TT the sensible thing to do, especially with the MBPC sizing issues

 

[brianmoooore]

what where they thinking faraday cage .

It is a Faraday cage, and they are absolutely safe inside of it, whatever condition the supplier's combined N & E is in. The potential problem occurs when they enter or leave it.

 

[Aaron b]

As far as I'm aware no testing has been completed. There is no management system detailing supervision or instruction, it's just a cabin used as storage with heating and lighting and I think it is reasonable to think any employee could use it.

Would these exceptions be for exceptional circumstances such as where the task would make a TT system impractical and testing would be conducted before each use? I struggle to see how an instruction would make the loss of a neutral less hazardous unless it was switched off before touching the true earth.

It's also appears to fed from a 32a socket that doesn't appear to be RCD protected. I think it's reasonable for me to refuse to test it.

 

[brianmoooore]

Why would you refuse to test it? Test and condemn.

 

[snowhead]

If you don't test it you can't document the faults with it (if any exist) and it will continue to be used in a potentially unsafe condition.

(Beaten to it byBrian)

 

[Aaron b]

Thanks, I suppose that's true. Should I conduct live testing though as surely it would fail on inspection? The main building has a couple of extraneous conductive parts not earthed, steel braces from the building that has recently had conductive parts installed near it and a new gas main. Would it be a bad idea to live test without that being sorted first?

 

[brianmoooore]

If you believe that it's unsafe to live test, then don't live test. You're the expert on site.