Cable entry question

[Joenicholson1996]

Hi all,
I am installing a new 3 phase DB and 110V DB. The current installation needs new DBS due to thier age and condition.
The cables used are all singles and ran in galvanised steel trunking and I am not replacing the single cores used.
My question is, is it alright to cut out a section in the DB that sits directly against a cut out section on trunking and use grommet strip to put around the cut out edges of the both the DB and the trunking so the singles can pass through safely?
Might sound like a daft question but I’m typically using SWA and tray when doing these jobs so have never came across the correct way to allow cable entry between metal trunking and a metal dB, keeping within the regs for IP and protection of cabling.
Any help is appreciated, cheers.

 

[SparkyChick]

Personally I would use conduit bushes, cut out holes in the trunking to match the DB and then connect the two using the bushes, but if there is a gaping hole in the trunking... maybe replace a short section of trunking???

 

[Leesparkykent]

Personally I would use conduit bushes, cut out holes in the trunking to match the DB and then connect the two using the bushes, but if there is a gaping hole in the trunking... maybe replace a short section of trunking???

Sometimes you struggle to but them up because of gland plate screws etc like you get on Hager boards. You would be best with a bit of Paxolin sheet.

 

[Pete999]

If I can ask why the 110V DB? just wondering

 

[Joenicholson1996]

If I can ask why the 110V DB? just wondering

The existing installation is in a workshop garage within a quarry, so the 3 ph+n board is for lights, heaters, compressors, welders etc.. and the 110v is for the 110v sockets around the workshop.

 

[Joenicholson1996]

Personally I would use conduit bushes, cut out holes in the trunking to match the DB and then connect the two using the bushes, but if there is a gaping hole in the trunking... maybe replace a short section of trunking???

I agree this would be the best way to do it, it’s definitely the way I would do it if I was doing a new installation (although I would just use SWA and tray if I were to do it from scratch). To make the job quicker though, would putting the two together and using the grommet strip as I described in the question be acceptable?
Cheers

 

[Pete999]

The existing installation is in a workshop garage within a quarry, so the 3 ph+n board is for lights, heaters, compressors, welders etc.. and the 110v is for the 110v sockets around the workshop.

Ah OK thanks very much for the update, must be an interesting job you have there.

 

[SparkyChick]

I agree this would be the best way to do it, it’s definitely the way I would do it if I was doing a new installation (although I would just use SWA and tray if I were to do it from scratch). To make the job quicker though, would putting the two together and using the grommet strip as I described in the question be acceptable?
Cheers

Seems like you may be viewing the solution as a bit rough and it seems like that goes against your usual approach. Would I be right?

I guess the answer is yes I think it's acceptable, I can't think of any reason it wouldn't be, except maybe containment of a fire within the DB. Providing the required IP ratings are maintained then I don't see a problem with it, except that it's possibly a bit rough and ready.

As @Leesparkykent pointed out you may have an issue with the gland plate.

 

[chris gray]

Can’t you get a manufactured t-piece for the trunking to drop down then fix that to the top of the dB?

 

[Spoon]

Products | Total Cable Management Solutions - trunking, cable tray and ladder: Unitrunk - http://www.unitrunk.co.uk/products/240340/326746

Maybe the above??

 

[chris gray]

Yep that would solve it

 

[Toneyz]

We only install Eaton and fit their trunking adaptor so only have to cut out trunking works as the same principle as Paxolin. If you use bushes and couplers use large and fit as many as you can for future usage.