Fuse board change with rear entry mounted on wood

[Michaelwgroves]

If you use rear entry you will compromise integrity of CU, you must therefore seal the openings. Two options I use is Rockwool rammed in tight, or Fire rated foam, just don't get carried away with foam............

 

[Octopus]

If you use rear entry you will compromise integrity of CU, you must therefore seal the openings. Two options I use is Rockwool rammed in tight, or Fire rated foam, just don't get carried away with foam............

Disagree.

There are no guidelines for ip ratings on the rear face

 

[Michaelwgroves]

It’s not for ip rating, it’s for protection against fire

 

[Octopus]

It’s not for ip rating, it’s for protection against fire

none of those either

 

[sparksfly]

The metal CU's in domestic is to contain a possible fire, not to be fire proof. Just use common sense, I also mount on wood ( so to speak!) and use a mini grinder to cut large holes in the back to accommodate a bunch of cables from all angles. So long as there are no unsheathed wires touching wood or metal...no problem. You only have to look at the old Wylex wood backed boards to see there was no issue with fire if installed properly. The only issue they had....a lack of space. I am not a fan of foam with any cables, lack of future maintenance.

 

[Spoon]

The metal CU's in domestic is to contain a possible fire, not to be fire proof. Just use common sense, I also mount on wood ( so to speak!) and use a mini grinder to cut large holes in the back to accommodate a bunch of cables from all angles. So long as there are no unsheathed wires touching wood or metal...no problem. You only have to look at the old Wylex wood backed boards to see there was no issue with fire if installed properly. The only issue they had....a lack of space. I am not a fan of foam with any cables, lack of future maintenance.

If this was always true then there would have been no need for the current reg on 'fire resistant' CU's

 

[Spoon]

There are no guidelines for ip ratings on the rear face

416.2.1. Live parts shall be inside enclosures or behind barriers providing at least the degree of protection IPXXB or IP2X

Doesn't this IP2X also apply to the back of CU's?

Might be me just being thick but what's the point of having a 'fireproof' CU due to fire risk and then cutting a bit hole in the back for the cables, which also lets the fire spread.

 

[Octopus]

Doesn't this IP2X also apply to the back of CU's?

Sides and bottom.

 

[Spoon]

Sides and bottom.

But 416.2.1. implies all sides.

what's the point of having a 'fireproof' CU due to fire risk and then cutting a bit hole in the back for the cables, which also lets the fire spread.

You understand what I'm getting at with my comment above.... It just makes no sense to have no IP rating for the back of the CU.

 

[Octopus]

You understand what I'm getting at with my comment above.... It just makes no sense to have no IP rating for the back of the CU.

I do.

But if you mount the CU on 19 mm supports, its hard enough to get a length of cable into the CU, let alone get your hand and fingers down.

However if you were to mount the CU on 300 mm supports then yo may have a point