Plastic compression glands for T&E into metal CU

[Pat H]

I'm sure this will have come up but what are the thoughts on cable entry into metal CUs?
Obviously from the rear is simplest but if cables have to come in from below then do we need to use metal glands or are plastic ok?
I assume for RFC its best for both legs of the circuit to enter together (although I think in terms of eddy currents as long as the L & N in the T&E are together that's all that's needed)

Been talk of ensuring the fixings to the wall are fire proof but even if use plastic raw plugs the screws are metal and I can't see a box falling off if it got really hot.
Also thinking some Intumescent sealant around the back to help seal the rear entry cables will effectively glue it in place anyway!

(Hey spelt topic right this time

 

[westward10]

The requirement is for the enclosure to be flame retardant, no mention is made of the cable entries. If you use stuffing glands with T&E you should really replace the rubber inserts with those that have oval holes through them. T&Es on ring finals can pass through separate entries. Wouldn't be worrying about using plastic wall plugs.

 

[Andy78]

Yes plastic glands are fine. The regulation concerns the material from which the consumer unit is constructed and not that of any peripheral parts used.

You can get gland inserts with shaped holes for T&E, single and double cables, to help comply with regulations surrounding entry through ferrous enclosures.

 

[Pat H]

Thanks. Yes I've got T&E glands with oval holes in them so was hoping it would be ok to use them.
If at all possible I try and avoid entry from the top and if I can always use the bottom so in the event of an internal fire there is less risk of a fire escape out of the top. Not always possible but often is.

 

[Nickj]

As said plastic is fine, many manufacturers have now updated their packaging on the plastic ones to state they are amendment 3 compatible as many are confused about it.

Those oval ones designed for t&e give a good tight seal.

 

[Octopus]

These ideas for metal cu's are fine in new installs but there are countless thousands of existing installs where like for like simply isn't feasible................. so you have to apply a large dose of common sense.

 

[buzzlightyear]

if it was not for jobs worth London fire brigade this would not be happening .half the men working for them part time sparks anyway. what do they know. for metal consumer units two strips on mdf
on back cover cable entrys to the back,and free extinguisher.

 

[Nickj]

Those jobs worths save a lot of lives and it's not a lot to ask that we assist them by making things as safe as possible.

I for one think the move to metal consumer units is a good thing. Metal can handle quite a lot of heat without bursting into flames unlike plastic.

 

[Pat H]

Isn't the most common fire cause in CUs loose termination screws? Apparantly, lets not say electricians lets say prople, don't think the neutrals have to be as secure as the lives.

 

[Nickj]

The cause wasn't only loose connections but also that the neutrals were shoved right up to the plastic housing. under load they were getting hot, causing a lot of heat and resulting in fire.

It's not helped by fact tha people don't have regular inspections of their installations. Terminations become loose over time and people can go decades before having an inspection.

Metal does significantly decrease chance of a house fire caused from consumer unit.

 

[Octopus]

I ripped out a 1980's metal Alex board today, built like a brick s... House with 2 screws for each of the incoming tails. Not a loose connection in the box, and it hadn't been touched for over 15 years

It's not just the box, the internal components are not built to last.

 

[westward10]

The cause wasn't only loose connections but also that the neutrals were shoved right up to the plastic housing. under load they were getting hot, causing a lot of heat and resulting in fire.

It's not helped by fact tha people don't have regular inspections of their installations. Terminations become loose over time and people can go decades before having an inspection.

Metal does significantly decrease chance of a house fire caused from consumer unit.

If there are sound terminations there shouldn't be a fire issue, metal or plastic. Must admit I have been using metal clad for years.

 

[buzzlightyear]

yes you are write pat h the idea is to contain the fire from spreading.most of the tails fitted in the isolator come out after you fitted them with crap screws .

 

[Pete999]

I'm sure this will have come up but what are the thoughts on cable entry into metal CUs?
Obviously from the rear is simplest but if cables have to come in from below then do we need to use metal glands or are plastic ok?
I assume for RFC its best for both legs of the circuit to enter together (although I think in terms of eddy currents as long as the L & N in the T&E are together that's all that's needed)

Been talk of ensuring the fixings to the wall are fire proof but even if use plastic raw plugs the screws are metal and I can't see a box falling off if it got really hot.
Also thinking some Intumescent sealant around the back to help seal the rear entry cables will effectively glue it in place anyway!

(Hey spelt topic right this time

Let me know if you find some metal rawl plugs

I'm sure this will have come up but what are the thoughts on cable entry into metal CUs?
Obviously from the rear is simplest but if cables have to come in from below then do we need to use metal glands or are plastic ok?
I assume for RFC its best for both legs of the circuit to enter together (although I think in terms of eddy currents as long as the L & N in the T&E are together that's all that's needed)

Been talk of ensuring the fixings to the wall are fire proof but even if use plastic raw plugs the screws are metal and I can't see a box falling off if it got really hot.
Also thinking some Intumescent sealant around the back to help seal the rear entry cables will effectively glue it in place anyway!

(Hey spelt topic right this time

Eddy currents on a SP&N CU Get real

yes you are RIGHTpat h the idea is to contain the fire from spreading.most of the tails fitted in the isolator come out after you fitted them with crap screws .

 

[Dave OCD]

Tighten up a plastic cable gland with a 'normal' round rubber insert and the insert will deform and seal perfectly round a T&E, IMO it's getting a bit silly and OTT.