PVC Back Box w/ Multiple Knockouts

LewisM · Aug 28, 2021

Hi does anybody know of single / double PVC back boxes that have multiple 20mm knockouts like metal clad? Or are plain with no knockouts ?

The ones with one 20mm and trunking knockouts don't really work as when cutting the 20mm hole the trunking entry normally splits even when bracing it.

LastManOnline · Aug 29, 2021

LewisM said:
Hi does anybody know of single / double PVC back boxes that have multiple 20mm knockouts like metal clad? Or are plain with no knockouts ?

The ones with one 20mm and trunking knockouts don't really work as when cutting the 20mm hole the trunking entry normally splits even when bracing it.

Marshall tufflex do them. Though I understand they are not A big seller in the UK so not cheap compared to metal. If you use a lot of them you can get them online more cheaply from any electrical wholesaler in ROI like CEF.

MJPD29 · Aug 29, 2021

MT ones should be readily available in cef

littlespark · Aug 30, 2021

There was a recent thread on the same subject. Might be worth a search.

SJD · Aug 30, 2021

Try the following links for the Marshall Tufflex ones:

1 Gang 35mm PVC Flush Box Round Corners with 20mm Conduit KO White (Sold in 1's)

Suitable for round conduit with 2 x 20mm entries on each of the 4 sides

www.cef.co.uk

2 Gang 35mm PVC Flush Box Round Corners with 20mm Conduit KO White (Sold in 1's)

4 x 20mm entries on horizontal sides, 2 x 20mm entries on vertical sides

www.cef.co.uk

Part of an 1980's estate round here was built with conduit in concrete walls, stranded & sheathed PVC multicore cabling the conduit, and these style of mounting boxes - won some kind of design award at the time - but a nightmare for electrical alterations.