Is it ok to run cable within a boxed vent pipe?

[magicstu]

I may get my head bitten off for this, but please be nice. I want to get the supply to my cooker replaced from 6mm to 10mm, but the existing route is almost impossible, but there is an easier route following the vent/stench pipe (that is boxed in ) through the bathroom and into the loft, then across to the front of the house and back down to the consumer unit. One company said they cant do it, as it passes through the bathroom, another has said it's ok because the cable is not part of the bathroom, and the boxed corner is completely built into the wall, I want to run the cable myself and get the electrician to do the final burying of the cable in the kitchen wall for the last 1.5 metres, and the final installation at the consumer unit with a new breaker, neither have an issue with that, its just the cable running down the boxed in pipework- Can anyone tell me if there are any regulations that it breaches? Thanks

 

[Guitarist]

I think that this is a good case of "things change". Most cookers will be quite happy on the 6mm/32a combo, yet with ranges becoming more and more popular it's time to take each situation on its own merit now.

 

[SPARTYKUS]

And, whatever we clever sparkies work out designwise, if the manufacturers instructions say 10.0mm then that overrides all other ideas.

 

[Richard Burns]

Unfortunately the manufacturers state 10mm in the wall, the OSG says up to 15kW is OK for the 6/32 combination and this cooker could be rated at 15.2kW, so the best idea would be to comply with this.
I assume they are applying reference method C for the wall and E for the cable to the cooker which allows it to drop to 6mm, not sure if they have taken ambient temperature into account.
Still think it may well be overkill with a diversity of 26A, but it does prevent problems, as you have a run available use that if you can and the cable would require 30mA RCD protection which may also cause problems with the potential leakage of these cookers.

 

[DNS1]

Those self-cleaning cycles tend to stuff up diversity calculations a bit...

 

[Engineer54]

Any Cooker, Oven and Hob, Range Cooker upto 15KW will sit happily on a 6mm cable protected by a 32A MCB/RCBO!!
That combination has been providing cookers with a suitable supply for over 60 years now. If this range cooker is 13.5KW as suggested then you don't need to upgrade to 10mm on a 40/45A MCB, ...END OF!!

If I go with the belling, then it does state in the instruction book (just downloaded a copy to see ) 45 Amp breaker,10mm cable to the control unit, and 6mm from the control unit to the appliance

As for that nonsense about supply cable to CCU to be 10 mm and from CCU to range 6 mm, should be telling you something about the person that came up with that little gem!! lol!!
The only time the supply cable would need to be increased would be due to derating factors eg distance/cable buried in insulation material etc!!

 

[magicstu]

getting confused now, the issue with the route for the cable is down to personal opinion of the electrician, so maybe they were both right? And looking at some of the answers, maybe I don't need it changed anyway??

 

[SPARTYKUS]

What does the manu instrs say

 

[magicstu]

if in doubt , contact a qualified electrician!! But yes it does state 10mm and a 45 amp mcb, but I am guessing they have to take worst case scenario on the values.

 

[Richard Burns]

The wiring regulations state we must take account of manufacturers instructions.
Your instructions do not seem too far out, so should be complied with, however in general they may be a bit of overkill, but would prevent problems. Because they may exceed the 15kW recommended limit (depending on the type of cooker) 6mm² and 32A breaker may not be suitable (but would probably work 99% of the time, cleaning cycles notwithstanding)
The cable run is not a problem, but fix it to the wall and not other pipework so as to prevent damage from future work.
The specs for the range of cookers you mention are like this

Fuel Type	Conventional oven	Fanned oven	Dual Variable grill (90/100 size)	Dual Variable grill (110 size)	Oven lamps	Single Variable grill (90 size)
Electric @240V	2.1kW	2.0kW	1.7 - 2.5kW 1.8 - 2.7kW	1.7 - 2.6kW 1.8 - 2.8kW	25W each	1.8kW
Appliance size	90E	100E	110E	Country Classic 100E
	220 - 240V	220 - 240V	220 - 240V	220 - 240V
	13040 - 15520W	12755 - 15180W	14100 - 16780W	12000 - 14280W

Connection between the consumer unit (45A MCB/Fuse) and the cooker control unit should be made with 10mm2 cable.
.
Connection between the cooker control unit and the appliance should be made with a 6.0mm2 twin and earth cable.

This appliance must be fitted using a double pole unit of 45 ampere minimum capacity with 3mm minimum contact at all poles.

Connection should be made with a 10.0mm2 twin and earth cable.

and so this would be the best solution.

 

[Engineer54]

Whatever load they specify will be ''connected load'' not the maximum load that can be drawn. All those loads will be clicking in and out via thermostatic control. Some loads will not be available when using another load (eg grill element with main oven element). Seems they are basing the recommended supply cable and OCPD seizes on the connected load, being permanently On, which you're never going to see!! I'd take those recommendations with a pinch of salt myself, another case where manufacturers instructions should not be taken as gospel, and in this case, with a 13.5 KW connected load, ignored!!

 

[Guitarist]

It's easy to quote what we all think, but if any electrician ran a 6mm in with a 32a MCB, then the unit tripped when the range went into self-cleaning, who's going to have to put things right FOC? The electrician of course. If the manufacturers quote 10mm on 40/50A, then just do it.

 

[Engineer54]

It's easy to quote what we all think, but if any electrician ran a 6mm in with a 32a MCB, then the unit tripped when the range went into self-cleaning, who's going to have to put things right FOC? The electrician of course. If the manufacturers quote 10mm on 40/50A, then just do it.

The wiring is already in place in this case!!

No way would i run a 10mm cable and with a 50A MCB for a cooker rated at 13.5 KW, you're welcome too though!! lol!!

Why would a self cleaning oven need anywhere near 50A anyway?? Besides, never found a self cleaning oven function that actually works anyway, just a total waste of electricity!!

 

[SPARTYKUS]

Been mentioned on another thread, but I installed a new "range" style cooker the udda day with induction hobs, and an oven that could have both grill, and the oven, on at t'same time, like. Couldn't quite believe it myself as never seen that, but it was a very expensive oven (retail £5.5k, ex display she got it for £3k), and the function that allowed this space/time anomaly was .............

pizza setting!

it came with (also a first) the cable fitted to the cooker, it was 10mm2 3 core high temperature flex. Thought it was a water pipe at first.

 

[Engineer54]

Been mentioned on another thread, but I installed a new "range" style cooker the udda day with induction hobs, and an oven that could have both grill, and the oven, on at t'same time, like. Couldn't quite believe it myself as never seen that, but it was a very expensive oven (retail £5.5k, ex display she got it for £3k), and the function that allowed this space/time anomaly was .............

pizza setting!

it came with (also a first) the cable fitted to the cooker, it was 10mm2 3 core high temperature flex. Thought it was a water pipe at first.

Well you can't argue with that, if it came prewired with 10mm flex (i'd have expected that flex to be gold plated if i'd have spent £5.5K!! lol ) So what was the KW rating of this very expensive range cooker??

 

[SPARTYKUS]

It was ridiculous. Maybe 15kw.