MK rapidfix, GAME CHANGER

GBDamo · Aug 12, 2021

MK have hit the market first with a lever connection based double socket.

I for one will be all over them as they are not too differently priced, £5.99.

littlespark · Aug 15, 2021

telectrix said:
doesn't any of youlot still use wood back boxes?

What’s a back box?

?

telectrix · Aug 15, 2021

typical Scotsman. no knickers under the kilt.

littlespark · Aug 15, 2021

telectrix said:
typical Scotsman. no knickers under the kilt.

You shouldn’t be bloody looking, tel!

nicebutdim · Aug 15, 2021

freddo said:
You can buy plastic boxes designed for burying, I forget who makes them though. Designed for walls that might rust metal back boxes.

Is it this sort of box? Smaller than a surface pattress and look like they're designed for this purpose.

Other than breaking with convention, is there any technical reason why metal boxes are preferable to PVC? Surely if well fixed, they're not going to be any more prone to movement or flexing than metal boxes.

freddo · Aug 15, 2021

That's the one, the price is probably the main reason for using metal boxes!

nicebutdim · Aug 15, 2021

freddo said:
That's the one, the price is probably the main reason for using metal boxes!

Yeah, spotted that after posting. Would certainly help in a damp wall, with cable run in conduit and bushed into the box.

LastManOnline · Aug 15, 2021

freddo said:
That's the one, the price is probably the main reason for using metal boxes!

That is the one. But that is not the price I pay. They are generally speaking equivalent in price to metal boxes over here. I assumed (wrongly) that these pvc flush boxes were widely in use in the UK as well.

nicebutdim · Aug 15, 2021

LastManOnline said:
That is the one. But that is not the price I pay. They are generally speaking equivalent in price to metal boxes over here. I assumed (wrongly) that these pvc flush boxes were widely in use in the UK as well.

Might be stocked at better prices in NI wholesalers, but I wouldn't have a clue. Just remembered seeing their odd size at one time and filed them away in my mind for later use.

LastManOnline · Aug 15, 2021

nicebutdim said:
Other than breaking with convention, is there any technical reason why metal boxes are preferable to PVC? Surely if well fixed, they're not going to be any more prone to movement or flexing than metal boxes.

For the first 10 years of my electrical career, pvc flush boxes did, nt exist, but when they arrived I found them to be better than metal in every facet.
1)Let's start with the faceplate screws. With metal boxes there is always the possibility of "nicking" a cable due to the poor design of the "eye".

2)With metal the 1mm of insulation can end up being crushed against the metal box, causing needless faults. I have dealt with countless faults over the years that a pvc box would have avoided

3)Retreading a damaged "eye" can be problematic and laborious. With plastic you can either replace or often often simply self-tap.

4)with metal the "knock - out" opens from the outside in. Fine on a new install but unhelpful on an existing install.
With pvc you simply drill through

5)The plastic box also electrically isolates the socket/ switch from then installation infrastructure

6) no sharp edges

7) pvc s always easier to work with

8) Is it time to shut up......

nicebutdim · Aug 15, 2021

LastManOnline said:
For the first 10 years of my electrical career, pvc flush boxes did, nt exist, but when they arrived I found them to be better than metal in every facet.

When you first mentioned this my immediate thought was PVC surface pattresses, but once I thought about those flush boxes it seemed quite reasonable.

I have very limited experience of PVC boxes, other than one old room with rough finished walls that I wired in surface conduit, and was very impressed with the boxes over their more brittle counterparts. In fact your first point was the one that immediately struck me back then.

Regardless, I'm about to start climbing a very steep hill and will be working in whatever manner my employer requires ?

Mike Johnson · Aug 15, 2021

PVC box's will not allow Earth testing from the face screw, other than that I can't see any disadvantage.

LastManOnline · Aug 15, 2021

Mike Johnson said:
PVC box's will not allow Earth testing from the face screw, other than that I can't see any disadvantage.

True. But usually only in the case of light switches. Most other accessories (sockets, 20 amp isolators etc) can still be tested from the face screw due to the internal strap which links the faceplate screw "eye" to the earth.

freddo · Aug 15, 2021

I've just had a quick look at the one I have here, It has little test points at the top for L and N, the test points are shallow so shrouded probes will have no problems making contact. It also looks like the earth terminal section is a separate unit, perhaps to allow for a clean earth model? The earth strap appears to be made of brass now rather than steel of the current 2 gang sockets, earlier ones used copper or a high copper content alloy. The white part of the socket is fortunately still made of urea formaldehyde and not the soft melty plastic some MK stuff is being made of now. The switches feel ok and plugs insert the same as existing MK sockets. Looks good!

[ElectriciansForums.net] MK rapidfix, GAME CHANGER

LastManOnline · Aug 16, 2021

LastManOnline said:
For the first 10 years of my electrical career, pvc flush boxes did, nt exist, but when they arrived I found them to be better than metal in every facet.
1)Let's start with the faceplate screws. With metal boxes there is always the possibility of "nicking" a cable due to the poor design of the "eye

9) No more earth fly leads required (yippee!!)

Zerax · Aug 16, 2021

freddo said:
I've just had a quick look at the one I have here, It has little test points at the top for L and N, the test points are shallow so shrouded probes will have no problems making contact. It also looks like the earth terminal section is a separate unit, perhaps to allow for a clean earth model? The earth strap appears to be made of brass now rather than steel of the current 2 gang sockets, earlier ones used copper or a high copper content alloy. The white part of the socket is fortunately still made of urea formaldehyde and not the soft melty plastic some MK stuff is being made of now. The switches feel ok and plugs insert the same as existing MK sockets. Looks good!

When used to spur off on a ring in a metal back box... that's 4 x cpc connections... only 3 wago connections available ?? Or is there capacity for the 4th one somewhere ?