What to put in 'Distribution reference' on forms?

[HappyHippyDad]

This is something I've been meaning to ask for sometime.

What do you guys put for 'Distribution reference, or distribution reference number' on the forms? Sometimes there is what looks like a specific number on the CU, but more often than not there is nothing to distinguish a particular CU.

 

[davesparks]

Was having a chat with a 2391 tutor today.
He was telling me that we can have 2 METs.

As I understand it there can only be one MET for an installation, this is the one that the earthing conductor connects to. Any other earth bar after this is an EMB (earth marshaling bar)

 

[Risteard]

As I understand it there can only be one MET for an installation, this is the one that the earthing conductor connects to. Any other earth bar after this is an EMB (earth marshaling bar)

I agree. The word "Main" in Main Earthing Terminal should be evidence enough of this. Others would be, as you indicate, Earth Marshalling Terminals.

 

[Deleted member 26818]

He did explain to me the difference between IP4X and IPXXD, which I always thought were just different ways of saying the same thing, also IP2X and IPXXB

 

[Risteard]

He did explain to me the difference between IP4X and IPXXD, which I always thought were just different ways of saying the same thing, also IP2X and IPXXB

If you look at the definitions they are quite different indeed. In fact IPXXB and IPXXD allow surprisingly large gaps.

 

[Deleted member 26818]

If you look at the definitions they are quite different indeed. In fact IPXXB and IPXXD allow surprisingly large gaps.

No greater than IPX2 or IPX4.
In fact IPXXB is 0.5mm smaller than IPX2.
I just didn’t realise the XXB/D related to internal access to live parts.

 

[Risteard]

No greater than IPX2 or IPX4.
In fact IPXXB is 0.5mm smaller than IPX2.
I just didn’t realise the XXB/D related to internal access to live parts.

I wouldn't agree that it's no greater. See this for example: IET Forums - Cable Trunking IP4X or IPXXD (BS 7671 Regulation 521.10.1) - https://---------------/forums/forum/messageview.cfm?catid=205&threadid=104323

 

[Deleted member 26818]

(Just realised I got the numbers in the wrong place, IP2X and IP4X.)
This is the info I have:
IP2X = will not allow a sphere with 12.5mm diameter to enter,
IPXXB = will not allow a British Standard jointed Finger to come into contact with live parts. British Standard jointed finger is 12mm diameter and 80mm long.
IP4X will not allow 1mm diameter wire to enter,
IPXXD will allow a 1mm diameter wire to enter, but must not come into contact with live parts to a depth of 100mm.

 

[Risteard]

Yes indeed, but a large object could enter so long as it doesn't come into contact with live parts. That is what I was pointing out about large gaps being possible with IPXXB/IPXXD.