Small galv trunking?

[timhoward]

Is anyone aware of any galv trunking that is smaller than 50x50. I'm drawing a blank online.
I've taken over a job that's used 16mm twin and earth (along with separate 16mm CPC) as a distribution circuit.
While I can arrange for most of it to be clipped direct, there's about 4m that is going to have to be chased in, and I don't want a 30ma RCD at the origin.
So I'd hoped to find smaller galv trunking.
Failing that, would a normal galv trunking lid screwed over the chase offer sufficient mechanical protection?
If not I guess I'm into cutting up 2mm mild steel sheets.
Bright idea's welcome.

None of this is what I want, it should have been SWA, but I can't justify replacing the whole cable because of this 4m problem.

(It's also a very horrible situation, and I'm keen to get this done asap. I'll explain more in the arms later)

 

[Rockingit]

Can you junction it each end to use 25mm conduit? (or near the end of the run to be able to slip it through, etc)

 

[Dustydazzler]

AS above , can you cut it and run through some 25mm galv conduit and then re-join it.

Not ideal but some jobs just need a naff solution and get in and get out

 

[Rockingit]

Is the wall thick enough to chase it >50mm??

Or...... if we're in the territory of naff solutions that work and comply to get us out of a hole...... a length of 22mm / 1" right angle section steel used to cap it.

2-3mm steel more than covers the requirements for mechanical protection. I had this problem years ago in the early days of the 17th when an inspector pulled up some meter tails that dropped to the CU from the ceiling and ran about a foot down/in the wall. No idea where it came from now but my solution was a bit of steel plate over the top as nothing else would be hard enough to not get drilled through by DIY.

 

[snowhead]

Sometimes called Top Hat channel,

External Cable Protectors | Cable Wire Basket | Cable Management System

These are currently being specified by a number of national builders for new housing projects.

directchannel.uk.com

 

[timhoward]

RE the galv channel; I knew about it but wasn't sure if 1.5mm thickness was enough to do the job. That would be easiest.

Is the wall thick enough to chase it >50mm??

Well if I go full depth with Metabo (40mm) and include the intended dot and dab finish in the measurement, technically yes.

Maybe if I do both, go > 50mm and use that galv channel no one can say I didn't try!

If someone still manages to get a drill into it after finding at least 3cm of air and then tapping something that sounds metalic then I think we've reached the limits of trying to saving idiots from themselves.

 

[loz2754]

The recommended minimum for non earthed steel protection is 3mm thick steel according to Electrical Safety First.

 

[timhoward]

The recommended minimum for non earthed steel protection is 3mm thick steel according to Electrical Safety First.

Good to know, thanks. So one of them screwed on, then another on top held with Stix like turbo (just kidding)
I haven't totally rejected galv conduit yet.

 

[loz2754]

There is a specific mention of not using several plates to make up the thickness.

 

[littlespark]

Just the trunking lid?

It’s only for protection from the front, right?

Capping… but a bit thicker

 

[UNG]

How about shallow unistrut as a cover it's a bit tougher than trunking lid

 

[timhoward]

As we are getting creative, I had wondered about cable tray backwards, but for mechanical protection is has rather a lot of holes in it!

 

[pc1966]

The suggestion from @UNG to use Unistrut inverted is good, as it is 41 x 41 outside or 41 x 21 (I think, from memory) and you can get it without the slotted holes.

If there is a separate CPC could it be bonded to the trunking solution? Even if you can't mechanically protect it against an idiot with a battery drill, then at least if drilled then it ought to ADS on the OCPD side.