IP2X

I think the third is an optional, usually to do with access by a bodily part. So B would be a finger, as opposed to the BS7671 " finger" ( IP2X ), so body part specific  .

Agreed - IP2X limits the size of holes in the enclosure; IPXXB limits access to hazardous parts by (a finger in this case) - which could be by say internal barriers or distance away from the hole, rather than necessarily making a requirement on the outer enclosure itself. An enclosure with big holes in it, but all internal parts insulated might fail IP2X but pass IPXXB.

http://www.beama.org.uk/asset/91D9AF47-079C-473C-95939F1ED12D064C.067E76BC-C59D-44B9-A4DF8C2E6F33F006/


  - Andy.

Very good document Andy, thank you. 

So enclosures are required to be at least IP4X or IPXXD top surface and IP2X or IPXXB elsewhere (416.2.2 and 416.2.1 respectively. Trunking is required to be IP4X or IPXXD all surfaces (521.10.1).

According to the BEAMA document there is a caveat that the probe may make contact with elements with basic insulation providing that insulation can only be removed by a tool or through damage. 

It would seem to me that the IPXXB and IPXXD stipulations are way less onerous. For example. IP4X requires the aperture to be not more than 1mm in diameter and a probe greater than 1mm should not pass through whereas IPXXD allows the 1mm probe to pass through a 35mm aperture for a distance of 100mm providing it does not make contact with live parts.

I have, for example an EICR in front of me where a C2 has been given for trucking lid that has gaps of 25mm. I am sure that it is a tad unsightly but if the BEAMA document is correct then it would not be in breach of the requirements in 521.10.1 albeit not meeting IP4X. 

Similarly, there seems to be a general stance taken that top surfaces of enclosures, like distribution boards, isolators etc, with apertures exceeding 1mm in diameter should be reported as a code but that is not necessarily the case if the probe cannot make contact with live parts within the 100mm length specified. 

I have, for example an EICR in front of me where a C2 has been given for trucking lid that has gaps of 25mm. I am sure that it is a tad unsightly but if the BEAMA document is correct then it would not be in breach of the requirements in 521.10.1 albeit not meeting IP4X.

That's why my reading seems to suggest - as far as I can tell you could run singles in trunking and for the smaller sizes (e.g. <50mm) leave the lid off completely - allowing easy access to the basic insulation - and it complies with IPXXD. How that's meant to square with protection against electric shock in the case of failure of the basic insulation I still don't understand.

 

Similarly, there seems to be a general stance taken that top surfaces of enclosures, like distribution boards, isolators etc, with apertures exceeding 1mm in diameter should be reported as a code but that is not necessarily the case if the probe cannot make contact with live parts within the 100mm length specified. 

Indeed and how that meets the supposed intention to keep dust out, I've again no idea.


  - Andy.