Meter board materials

[wookey]

I need to extend my meter board to fit stuff on neatly. The requirement seems to be that the boards are reasonably fire-resistant. I can buy kosher Wooten flame-retardant meter boards from CEF, but they don't do one big enough (I want about 600x450 to get two CUs on).

Can I just use a nice bit of 18mm OSB I have to hand? That doesn't seem like it's going to catch fire much. Maybe paint it with something? Otherwise I could buy fireproof MDF from this lot: https://www.mdfdirect.co.uk/product/fla ... t-to-size/
Not sure if the local builders merchant have something suitable.

Will any old reasonably solid planks do in practice? Wood is not renowned for its fireproofness, but that's what all meter board are made from. My ancient ones from probbaly 60's and 80's extension look like varnished chipboard.

I could just use the entirely fireproof plaster wall, but then things like clipping cables involve a lot of masonry-hole drilling, and I can't pass cables underneath.

Suggestions welcome.

[chris_n]

https://www.jointingtech.co.uk/Meter-Bo ... -Chipboard

[AGT]

Or a tile backer board like what topops tiles sell seem to be popular with the PV inverter installs

[Beau]

I've just had an electrician replace our consumer unit and all he wanted behind it was a piece of 18mm ply.
Should I be concerned?

[Stinsy]

You can buy the exact stuff from electrical wholesalers:

https://www.cef.co.uk/catalogue/categor ... enclosures

[Stinsy]

I've just had an electrician replace our consumer unit and all he wanted behind it was a piece of 18mm ply.
Should I be concerned?

It might look a bit like crappy chipboard, and it is to some extent, but the correct stuff has been treated to be flame retardent...

[sharpener]

Or a tile backer board like what topops tiles sell seem to be popular with the PV inverter installs

I would think almost any mineral based board would do to provide a surface that won't be ignited by a fire in switchgear.

I had to fit a new chipboard panel in the loft for our first PV inverters. To face it I used an offcut of 6mm calcium silicate board we had left over from a loft conversion. Inverter installers were well impressed.

The original requirement was to line a timber partition adjacent to the only staircase to provide a 30 min fire barrier . The silicate board was only half the thickness of the other approved products so looked a lot better without needing to remove/re-fit the skirting and architraves.

[wookey]

You can buy the exact stuff from electrical wholesalers:

https://www.cef.co.uk/catalogue/categor ... enclosures

Yes. As I said, I discovered that, but they don't sell one quite big enough. I could buy two and 8 mounts, but was hoping to avoid that. Chris_n's suggestion comes to about the same cost as two cef boards even with delivery so looks like a good answer. In fact they look like a very useful supplier I was not aware of with a more 'electrician' oriented range than CPC.

Tile backer is easy to get but most of them don't take screws/nails very well/at all do they? Which is the main reason for not just using the wall directly.

[Stinsy]

Tile backer is easy to get but most of them don't take screws/nails very well/at all do they? Which is the main reason for not just using the wall directly.

Cement board is fine to screw into so long as you use a rawl plug. If you're screwing through it, a washer is advisable.