Sealing a consumer unit entry points??

[leebut]

Hello Guys


I'm going to put my Tin hat on and close the curtains so the Regs police can't arrest me for asking this question again, I can only find old threads pre 18th edition so please advise me if I'm missing something


I've just been watching a guy on Youtube doing a board change who's said that to comply with the 18th edition of the Wiring Regulations you must seal ALL entry holes into a consumer unit regardless of them coming through the bottom, top, sides or rear entry with a suitable intumescent mastic to stop the spread of fire into the fabrication of the building!!!


I personally am NOT aware that anything changed in the 18th Edition to say all entry points have to be fire sealed I've been looking online tonight and can only find write ups from "Wiring Matters"

Stating


Sealing of wiring entries
It is important for the installer to seal all openings into the enclosure or cabinet for cables, conduits, trunking or ducting that remain after the installation of cables - see Figure 6. The intent of the sealing is to ensure that, as far as is reasonably practicable, any fire is contained within the enclosure or cabinet and the escape of flames to the surroundings of the cabinet or enclosure or into conduits trunking or ducting is minimised, as intended by Regulation 421.1.201.
Good workmanship and proper materials must be used, and account must be taken of the manufacturer’s relevant instructions, if any.


Regulation 421.1.201 Does not mention sealing any apertures in a consumer unit with, grommets, glands or sealant and does not mention that the Metal clad board cannot be fitted to a timber backboard. So why is the IET saying we are to be sealing the holes , personally I've been installing all my boards with cables entering from behind and mounting my boards on the existing wooden backboards using a length of stick on trunking as a framework around the consumer unit.


Am I wrong???

 

[ipf]

The answers I've been told is, the fires start from loose terminals in the tops of MCB's and the flames melt the plastic CU which spreads the fire, so any opening below the top of the CU doesn't need sealed, hence the reason why I bring my cables in through the back knock outs and I only put flexible grommet strip round to stop damage to the outer sheathing.

Agree. There's nothing wrong with a piece of ply stood off the wall for rear entry...

 

[leebut]

Agree. There's nothing wrong with a piece of ply stood off the wall for rear entry...

I mount my boards on a frame of sticky trunking using longer screws with washers so the plywood is further away from the CU so less chance of scorching or fire, the idea of the metal CU is to take away the accelerant so I don't understand the logic of sealing the knock out making any additional work harder to carry out

 

[ipf]

I mount my boards on a frame of sticky trunking using longer screws with washers so the plywood is further away from the CU so less chance of scorching or fire, the idea of the metal CU is to take away the accelerant so I don't understand the logic of sealing the knock out making any additional work harder to carry out

To tell you the truth, I don't do many these days but I've access to various bits of ply and wood machines so it's just make up as required......don't even use grommet strip...make the wood slots smaller than the metal and smooth nicely...no problem. Good ply wood is no fire hazard.

 

[Charlie_]

I just make sure all the terminations are nipped up nice and tight

 

[Charlie_]

I take it commercial/industrial sparks are better than domestics?

Seeing as they can be trusted with plastic boards

 

[ipf]

I just make sure all the terminations are nipped up nice and tight

Yeah......but with the class of some of todays terminations...…….and some working on 'em...

 

[Risteard]

I take it commercial/industrial sparks are better than domestics?

Seeing as they can be trusted with plastic boards

Well presumably the assumption is that there are plenty of laws in the workplace to ensure that the installation is maintained adequately, etc. Obviously this isn't always the case particularly with smaller businesses.

 

[Devonchris]

I mount my boards on a frame of sticky trunking using longer screws with washers so the plywood is further away from the CU so less chance of scorching or fire, the idea of the metal CU is to take away the accelerant so I don't understand the logic of sealing the knock out making any additional work harder to carry out

So in effect, you form a chimney in a plastic flammable material, (I'm assuming plastic as I've never seen sticky back metal trunking), with an opening from the CU into the chimney? Bit like cladding a tower block??

 

[Intoelectrics]

If You are going to mount the CU on wood then just paint the wood in a fire retardant paint first.

Home | Rawlins Paints

www.rawlinspaints.com

I paint it in something like this, you can get it cheaper than quoted on the link.
I bought a tin a while back and coated a few sheets of ply, I then just cut out what I need for the CU then touch in the cut edges with the paint.
Its probably a bit over kill, but for a few extra quid it gives me peace of mind. I print off the data sheet to the paint and put it in with the EICR.

 

[Dustydazzler]

Why don’t manufacturers just make a ‘19th addition’ non combustion bomb and fire proof surface mounting accessory for domesticated consumer unit wiring.

Kind like a surface wiring patters just much larger and supply with it a tube of flame retardant sealant to caulk in any gaps or holes

 

[Midwest]

If You are going to mount the CU on wood then just paint the wood in a fire retardant paint first.

Home | Rawlins Paints

www.rawlinspaints.com

I paint it in something like this, you can get it cheaper than quoted on the link.
I bought a tin a while back and coated a few sheets of ply, I then just cut out what I need for the CU then touch in the cut edges with the paint.
Its probably a bit over kill, but for a few extra quid it gives me peace of mind. I print off the data sheet to the paint and put it in with the EICR.

Why bother, the new CU being metal, means it won't catch fire

 

[richy3333]

Bunch of old women.

@Reevio Are you the bloke off Youtube? I'm sure he's from around Oxford area?

 

[leebut]

Yeah......but with the class of some of todays terminations...…….and some working on 'em...

Sometime people are over tightening the terminals and they’re damaging the cable connection hence why they want us to us Torque screwdrivers

Why don’t manufacturers just make a ‘19th addition’ non combustion bomb and fire proof surface mounting accessory for domesticated consumer unit wiring.

Kind like a surface wiring patters just much larger and supply with it a tube of flame retardant sealant to caulk in any gaps or holes

why do we just line the CU with asbestos!!

 

[Dustydazzler]

Sometime people are over tightening the terminals and they’re damaging the cable connection hence why they want us to us Torque screwdrivers

why do we just line the CU with asbestos!!

Near every site sparks I watch doing a consumer unit , uses an impact driver anyway (and no I’m not joking) annoyingly I can’t find the video but there was a new build sparks on you tube who installed a brand new 17th Ed consumer unit using nothing but an impact driver.

Box it in using asbestos would probably achieve a better fire rating ?

 

[Andy78]

@Reevio Are you the bloke off Youtube? I'm sure he's from around Oxford area?

From his previous posts it would appear that he is.

You'd have thought he'd have had some input of a slightly more technical and insightful nature given his love of speaking in public on such matters.