Trunking in house (18th edition)

[peterhyper]

I admit to not taking too much notice of the 18th edition changes as I only took my 18th exam last week (no excuses I am not a good spark like most on here).

I have a flat to do that needs the lighting circuit rewired, but being the ceilings are like concrete and the owners don't want major disruption, it will be done in mini trunking. I usually use self adhesive trunking and seal it with white no nails to give it a strong fixing as drilling through concrete to fix screws in will be an absolute nightmare. So where do I technically stand not using metal fixings to secure it?

 

[Spoon]

So where do I technically stand not using metal fixings to secure it?

You have to use the proper fixing to stop the cable from collapsing, in case of a fire. This will involve drilling.

 

[Michael Sands]

You stand in front of the judge and try to explain why someone was strangled by your dangling live wires when trying to get out of a burning house

 

[telectrix]

what's the chance of fitting false ceilings on a 3 x 2 studding?

 

[buzzlightyear]

what's the chance of fitting false teeth and going out studding

I would def go with that .

 

[Andy78]

I've always fixed adhesive trunking anyway, the adhesive is for holding it to the wall while you fix it
D-line fixings inside the trunking too.

 

[freddo]

drilling through concrete to fix screws in will be an absolute nightmare.

Why is that? SDS drills are mighty powerful, then an impact driver to drive a concrete screw into the hole. Did a load of steel conduit last month into concrete walls and ceilings that way.

 

[Dustydazzler]

Unfortunetly you can no longer simply use sticky back trunking for re-wires. The plastic trunking and more importantly the cables in the trunking have to be fixed to the fabric of the building using a metal fixing.
There are many ways to achieve this from purpose made clips to a bit of cut up metal bandy strap.
Either way every single method will require fixing to the ceiling in this case.
Nomore nails glue will not meet the new regs

 

[billyblade]

Drilling through concrete using an SDS drill and good quality bits is not a nightmare.
Drilling through concrete with a combi drill and percussion drill bits is

 

[peterhyper]

Thanks guys.

 

[Squid]

How old is the flat and how is the current wiring run around the flat, did a job with my uncle many years back in a 1920's block and managed to utilise the old conduit and run in singe core cables.

 

[peterhyper]

How old is the flat and how is the current wiring run around the flat, did a job with my uncle many years back in a 1920's block and managed to utilise the old conduit and run in singe core cables.

Not sure how old the flat is, but I would guess 1940s. The current lighting circuit is in singles and is run inside steel conduit. I always try pulling singles through, but I haven't had much luck with similar set ups in the past.

 

[telectrix]

a bit of chip fat mixed with fairy liquid does wonders. cables will end up clean and greasy at the same time.

 

[peterhyper]

Forgive my naivety, but if I run mini trunking along the ceilings, are the metal fixings to support it supposed to completely cover the mini trunking. The reason I ask is because if the fixings are inside the trunking and a fire started, then the trunking covers would just collapse and the cables fall out?

I appreciate this new requirement is as a result of a very unfortunate incident causing the deaths of firemen, but in reality aren't there many other unsafe practices occurring everyday that are ignored (unless a part pee log is used).

Running 16mm mini trunking in a corner of a room is highly unlikely to trap someone in a building.

Also, if the mini trunking is fitted above the skirting boards, does that also have to adhere to the same criteria in case a person under 6" tall gets trapped under it?

 

[telectrix]

sticky back the trunking on, then use metal clips on the cable inside the trunking. several varieties to choose from, even more than heinz57.

 

[Charlie_]

Instead of ceiling lights have you considered wall lights or 5 amp sockets instead?

 

[peterhyper]

Instead of ceiling lights have you considered wall lights or 5 amp sockets instead?

Good question, but they want ceiling lights in the same place as the existing ones.

 

[Andy78]

Like this Peter ...

 

[telectrix]

at least with concrete ceilings he can fit 50kg chandeliers without reinforcement.

 

[Charlie_]

Or if you want to be really snazzy,
go for illunimated coving or
Led channel across the ceiling

 

[telectrix]

Or if you want to be really snazzy,
go for illunibated coving or
Led channel across the ceiling

now noww, youse gonna get a dumb for illunibated. .

 

[freddo]

The current lighting circuit is in singles and is run inside steel conduit.

If everything is going in the same place, I'd be using the existing conduit (unless it's really badly corroded).

 

[peterhyper]

So if I use 100mm wide plastic trunking on a ceiling, the actual cover doesn't have to be secured, so that could potentially catch fire and fall down and trap someone (weighing far more than 16mm mini trunkng).

 

[Squid]

at least with concrete ceilings he can fit 50kg chandeliers without reinforcement.

Just buy a table lamp, much easier........

 

[Squid]

Not sure how old the flat is, but I would guess 1940s. The current lighting circuit is in singles and is run inside steel conduit. I always try pulling singles through, but I haven't had much luck with similar set ups in the past.

Any cover plates on the ceilings for the junction boxes or the walls for the sockets?

 

[Charlie_]

now noww, youse gonna get a dumb for illunibated. .

Hahaha thanks for the tip off and not going straight in with the tag

 

[Spoon]

So if I use 100mm wide plastic trunking on a ceiling, the actual cover doesn't have to be secured, so that could potentially catch fire and fall down and trap someone (weighing far more than 16mm mini trunkng).

I think you are missing the point of the change mate.
Try being a firefighter for a day and then see how you feel.
The reg is changed to stop entanglement with cable. This can happen at any height. Feet, arms, heads & breathing equipment can all get entangled. When a house is full of smoke visibility can be virtually non-existent. They may have to feel their way through the house.

 

[peterhyper]

I think you are missing the point of the change mate.
Try being a firefighter for a day and then see how you feel.
The reg is changed to stop entanglement with cable. This can happen at any height. Feet, arms, heads & breathing equipment can all get entangled. When a house is full of smoke visibility can be virtually non-existent. They may have to feel their way through the house.

I clearly am missing the point. So trunking 6" from the ground above skirting boards has to follow this criteria in case it falls on anyone, and as per my previous post can 100mm plastic trunking covers be fitted unsupported?

 

[Spoon]

I clearly am missing the point. So trunking 6" from the ground above skirting boards has to follow this criteria in case it falls on anyone, and as per my previous post can 100mm plastic trunking covers be fitted unsupported?

If you use the word 'entangles' rather than 'fall' then it makes more sense.

Plastic trunking will melt in a fire. It will not entangle a firefighter like copper cable can.

 

[Charlie_]

I clearly am missing the point. So trunking 6" from the ground above skirting boards has to follow this criteria in case it falls on anyone, and as per my previous post can 100mm plastic trunking covers be fitted unsupported?

Metal trunking would be the best option in that scenario

 

[Tony Reidy]

I admit to not taking too much notice of the 18th edition changes as I only took my 18th exam last week (no excuses I am not a good spark like most on here).

I have a flat to do that needs the lighting circuit rewired, but being the ceilings are like concrete and the owners don't want major disruption, it will be done in mini trunking. I usually use self adhesive trunking and seal it with white no nails to give it a strong fixing as drilling through concrete to fix screws in will be an absolute nightmare. So where do I technically stand not using metal fixings to secure it?

Use trunking but fix cable with metal clips internally

 

[magnoliafan89]

Who the hell only relies on the sticky back of trunking....especially on a ceiling?!?!

If u drill the trunking to the ceiling before u screw the screw in put it through the fire clip...this holds the cables in place after the lid has fallen or melted off.

 

[peterhyper]

Who the hell only relies on the sticky back of trunking....especially on a ceiling?!?!

If u drill the trunking to the ceiling before u screw the screw in put it through the fire clip...this holds the cables in place after the lid has fallen or melted off.

Only fools would probably rely on sticky back trunking especially on a ceiling (?!?!), hence why I said I use no nails. I've never had any issues whatsoever with mini trunking when I've used it on concrete ceilings with decent no nails (sticks like s**t works well).

 

[UNG]

Only fools would probably rely on sticky back trunking especially on a ceiling (?!?!), hence why I said I use no nails. I've never had any issues whatsoever with mini trunking when I've used it on concrete ceilings with decent no nails (sticks like s**t works well).

Was the customer happy when you started a fire under it to test the fire resistance of the trunking fixings
I'm not sure how you intend to secure the cables in the trunking or are you using no nails for that as well

 

[peterhyper]

Was the customer happy when you started a fire under it to test the fire resistance of the trunking fixings
I'm not sure how you intend to secure the cables in the trunking or are you using no nails for that as well

I use some Harry Monk for that (works a treat). Occasionally the customer gets the hump when I start producing it, but I tell them it's a natural substance and good for the enviroment.

 

[Frugby]

This isn’t a new requirement as escape routes were covered under 17th. Reg applies to all areas just an improvement. I am amazed this is even up for discussion?

 

[leebut]

I’ve just carried out the same type of installation in a flat in Manchester, luckily for me my job was having false ceilings throughout due to the concrete ceilings having cracks along the slab joints, the customer also wanted down lighters in all the rooms so easy for me, we put up the British Gypsum MF ceiling system.

If your using mini trunking your going to have to use metal mechanical clips throughout you could use a Hilti nail gun to fix your fire clips to the concrete, I used a concrete nail gun to fix my ceiling channels to the walls

 

[leebut]

This isn’t a new requirement as escape routes were covered under 17th. Reg applies to all areas just an improvement. I am amazed this is even up for discussion?

It’s not just fire escape route now it’s all parts of the installation that have to have fire rated clips to stop the cables dropping

 

[rapparee]

Who would honestly want to look at mini trunking in their house.

I think I'd do without the rewire

 

[Spoon]

It’s not just fire escape route now it’s all parts of the installation that have to have fire rated clips to stop the cables dropping

@Frugby just stated that fire rated clips have been in the regs since the 17th. Yes the 18th have now gone further with it.
I'm also with him on why people are still questioning this.

 

[Toneyz]

Who the hell only relies on the sticky back of trunking....especially on a ceiling?!?!

Data guys.

 

[pirate]

It isn't that difficult...
Could a cable fall in a fire?
If yes, fix it so it can't...don't use plastic plugs or cable ties, and if in plastic trunking, use internal metal clips, properly fixed...wall-dogs or similar. It's easy to find metal fixings these days, so why bother trying to get round the regs?
Use your catalogues, read them, see what is out there.
You are professional electricians, you keep up to date with the latest trends, you want to use the brilliant new stuff that is better than ever before, so why prevaricate?
Oh...it saves a few pennies?
Try saving a few lives...that is the professional way!
My "plumber" said to me, he thought the cost of the tube supports for push-fit plastic plumbing was ridiculous...made him take them all out...a pack of 20 was £3...
I'd rather he added £20 to the price!
This is a stupid debate, frankly. Anyone who finds that a few clips at 20p each is a deterrent should be in another job.

 

[Ashley-Joseph]

Now days people use steel conduit and it looks modern and it would stop the cables from hanging or you could chase and cap the cables the get it skimmed.