Supporting Wall Removal / RSJ and Electrical Cables

[Mart_]

Hi all,

Having a steel put in next week and having the wall removed. As this is all new to me I'm unsure how it all pans out with the electrical cables.

The pics are of the same part of the wall but different sides (kitchen/diner) what's the usual course of action here?

Can you route a channel through the boards for the cabling? or do they need to be fed through pre drilled holes in the steel? or can they loop under the steel?

Thanks

 

[flameport]

How is the steel being installed ?
1 - below those existing timbers, or 2 - will those be cut and the steel installed flush?

If 2, then what depth is the steel, compared to the depth of the existing joists?

 

[Mart_]

Hi flameport

Yes forgot to mention, its going to be flush with the ceiling.

Steel = 178x102x19
Existing Joist depth = 179

Does that mean there's going to be 10mm free below the steel?

Thanks

 

[chivers67]

If they don't do through the RSJ they'll need mechanical protection as the Depth will be less than 50mm.

If they go through the joist you'll need some kind of grommet (or conduit allow for derating if this is the case) so it doesn't rub on metal when any movement occurs due to expansion/contraction.

 

[ban-all-sheds]

If they don't do through the RSJ they'll need mechanical protection as the Depth will be less than 50mm.

Only applies to depth below floors, not above ceilings.

 

[chivers67]

There's no harm in protecting something in a ceiling like that, it's far more likely to get a drawing pin or nail in it when someone puts up Christmas decorations or similar.

Or do you disagree?

 

[flameport]

Does that mean there's going to be 10mm free below the steel?

Theoretically, although that will still be very tight for cables and in reality there may not be any space at all.

Holes through the steel will be a far better and much easier option.
Get the fabricators to drill one or more holes before the steel is delivered.

 

[chivers67]

If you haven't got any holes the best drill bit I've used is the Dewalt metal bits

https://www.screwfix.com/p/dewalt-hex-shank-extreme-2-hss-drill-bit-12-x-151mm/7768v

 

[Mart_]

Thanks for the replies and link.

If I was to drill through the steel or got the fabricators to do it, would this cause an issue with the council when they come out to inspect?

Would I first have to go through the structural engineer for him to agree?

 

[Taylortwocities]

Your building contractor (if he is any good) will know what can be done with the cables.
You will need to check with your structural eng if holes are OK given the load/stresses. They may not be needed, depending on the answer to the above.

Remember. How will you get the cable through the holes (if you have some). You'd have to either find the ends and re-run the cables, or cut the cables and rejoin them. How would you do that, bearing in mind the joint will not be accessible?

 

[Mart_]

I've decided the both ceilings are coming down now. They are artexed anyway so was going to skim. New boards and fresh skim should give a much nicer finish.

In doing this I'm hoping whatever the builders advise a complete blank canvas as far as the ceiling goes will help.

Any cutting of cables and I'll obviously get an electrician onsite.

 

[ban-all-sheds]

There's no harm in protecting something in a ceiling like that, it's far more likely to get a drawing pin or nail in it when someone puts up Christmas decorations or similar.

Or do you disagree?

1) I don't know of anybody who nails Christmas decorations to the cieling.
2) I don't know of any drawing pins with spikes longer than the thickness of plasterboard.

 

[ban-all-sheds]

Any cutting of cables and I'll obviously get an electrician onsite.

Arguably any re-routing or re-concealing of cables is electrical work. It may not be notifiable in its own right, but as it is part of a larger project which does need BR approval, be aware of the possibility that they may ask about electrical work.

 

[JohnW2]

Steel = 178x102x19
Existing Joist depth = 179
Does that mean there's going to be 10mm free below the steel?Thanks

Maybe I'm misunderstanding, since I'm confused by that arithmetic - 179-178 = 1, not 10, and nor would your figures make any sense as centimetres.

Kind Regards, John

 

[ban-all-sheds]

Maybe the SE is Bloody Stupid Williams.