6mm t & e connected to 2.5 t & e

[Dantheman]

what would happen if you connected 6mm twin and earth tho a 2.5mm twin and earth via jb ??


Many thanks

 

[Dantheman]

24kw ***

 

[Marvo]

I'm assuming the supply is just for controls and ignition etc and the boiler is gas/coal/oil fired.

I would suggest you make the joint using ferrules and a crimper and heatshrink insulation over the top. This would be considered a maintenance-free joint. I would also extend the cable using a length of 6mm FT+e as well. It's a couple of quid extra but there's less chance that it would result in an overloaded cable at a later date if someone replaces the 6A MCB.

 

[Richard]

I'm assuming the supply is just for controls and ignition etc and the boiler is gas/coal/oil fired.

I would suggest you make the joint using ferrules and a crimper and heatshrink insulation over the top. This would be considered a maintenance-free joint. I would also extend the cable using a length of 6mm FT+e as well. It's a couple of quid extra but there's less chance that it would result in an overloaded cable at a later date if someone replaces the 6A MCB.

Hi,

What does the 'F' in FT+e stand for? Never come accross that one!

Cheers

 

[edward cooper]

Am i missing something. Dont the regs state that when linking two cables of different csa then it needs to be done via a fused connection. Or are the voices in my head starting again. linking two cables with no protection for the smaller cable is asking for trouble in future.

 

[SimpleSimon]

Am i missing something. Dont the regs state that when linking two cables of different csa then it needs to be done via a fused connection. Or are the voices in my head starting again. linking two cables with no protection for the smaller cable is asking for trouble in future.

It'll be fused at the switch for the boiler.

Sent from my GT-I9100 using Tapatalk

 

[Marvo]

Hi,

What does the 'F' in FT+e stand for? Never come accross that one!

Cheers

Flat.....I assume he's talking about as opposed to Surfix? Maybe it's a local name not used in the UK?

 

[edward cooper]

will the fused connection be within 3m of the joint? I think it needs to be.
Think it really would be best to crimp new 6mm to old 6mm heat shrink etc then fuse down at boiler then add your new cable to boiler which will be flex wont it. I think this is safest. (What you all think as im new to this).

 

[Knobhead]

If the protection is rated to the smaller cable there’s no problem.

 

[sparky1502]

why pay someone to do it when we can walk you through the whole process

 

[SirKit Breaker]

the 6mm is from the board to the landing are (old shower feed already on a jb) boiler is going in the landing aprox about 10m away (round corners and so on) Need to pick the power up for the boiler spur near impossible to tap off the ring. The cables run under floor boards
Im just asking for advise it’s not me doing it it’s the plumber

I didn't mean to be sarcastic, i was just answering the question. There is no problem with you joining a smaller cable to a larger cable or vice versa. Just make sure that the circuit protection is suitably derated for the smaller cable. If you are just using it for a boiler feed, then replace the existing MCB with a 6a one (up to 20a would be ok if you are going to a fused spur in 2.5mm), and make some sort of note at the CU so no one comes along and puts a 40 or 50a one back in at some time.

Cheers.............Howard

 

[oldtimer]

Going from 6mm to 2.5mm is not a problem as lomg as you fuse rate for the 2.5 ie 16 amps just been to a job where the 40A supply from the DB to the shower switch is 4mm at 5 metres and the switch to shower is 6mm

 

[DNS1]

As I understood, as long as the calculations were done and the protective device was selected with the smallest cable in mind, everything would be fine.

Nothing wrong with increasing the cable csa, just decreasing it can be a problem.

Is it worth considering the fact that someone might change the protective device at a later date?

 

[oldtimer]

DSN1 that fine until a "stupid" plumber goes into a house and changes the 7kw shower for a 9kw saying its ok as there is a 6mm at the shower and 40A MCB and a short run.

Also just to add you are only as strong as your weakest link or in other words in my veiw you should rate the circuit for the smallest cable as good practice

 

[Inteificio]

You are trusting a plumber with your electrics?

I don't even trust them with my pipes =-)

 

[telectrix]

Hi,

What does the 'F' in FT+e stand for? Never come accross that one!

Cheers

flat????