Connection a junction box to a 10mm ring
- Thread starter sharan17a
- Start date
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B
breezer
you obviously do not understand since you have to ask, but i shall explain.
diversity allows 5A MAX for the socket, NO MORE, its for plugging in things like extractor hood, electric knife , electric tin opener
diversity allows 5A MAX for the socket, NO MORE, its for plugging in things like extractor hood, electric knife , electric tin opener
B
breezer
shavvy said:And what is so wrong with connecting the hob to to the dedicated cooker curcuit
nothing, so long as it is just the hob on its own, which is not what this post started as, the poster wanted to connect the oven AND hob to the cooker cct, which is a no, no
by the way shavvy, my coat is here, yours is over there i suggest we go
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I've a single fan oven, and a seperate electric induction hob. I've got an electrician coming tomorrow to run a new connection from the main circuit breaker to the kitchen, I'll then be able to wire the hob into this new socket.
Tricky this electrical lark, ain't it?!
Tricky this electrical lark, ain't it?!
Dear lord what is wrong with you guys - been drinking all day???
Your mission, should you choose to accept it - find me a domestic hob and a domestic oven which together draw enough current to cause a 10mm² to catch fire.
What knowledge do you have of the MCB protecting the cable? How do you know that an oven + separate hob will overload it and trip the breaker?
Your mission, should you choose to accept it - find me a domestic hob and a domestic oven of such ratings that the standard diversity calculations produce an answer of more than 40A (IMHO it is reasonable to assume that nobody would put in a 10mm² cable for anything less).
If we change the figure in the diversity calculation from 5 to 13 for an oven, that allows us to have a hob of 15kW on a 40A breaker (15kW = 65.2A, 10 + (55.2 x 0.3) + 13 = 39.56)
Your mission, should you choose to accept it - find out what BS 4177: 1992 (1993). 'Specification for cooker control units' says about the rating of the built-in socket.
It's interesting to read what the OSG has to say, in Table 1B "Allowances for diversity"
In the column headed "Purpose of final circuit.."
- 3. Cooking appliances 10 amperes +30%fl of connected cooking appliances in excess of 10 amperes...
Sharan17a wanted to know if he could get a junction box which would handle 10mm² cables, and you two went off on some mad tangent making claims which do not stand up to even a cursory analysis.
Sharan17a - if it's not too late, here's one:
and as ryanj can testify, it will easily accept 2 x 10mm² cables in one side.
As to whether you can connect both appliances to the same CCU, I'll ask the questions that nobody seems to have bothered themselves with so far.
1) What is the rating of the hob?
2) What is the rating of the oven?
3) What is the rating of the MCB on the circuit?
4) Will both appliances be within 2m of the CCU?
How do you know that? This is a 10mm² cable, its nominal rating is 64A. How can you possibly say that a separate hob and oven will overload it? If this was a single cooking appliance, i.e. a freestanding electric cooker, the diversity calculations would allow you to connect one of up to 39kW (39kW = 170A, 10+(160 x 0.3)+5 = 63). Also, what possible justification do you have for saying that overloading it will cause a fire? Do you have some knowledge of the size of MCB protecting this 10mm² cable? Is it well over 100A or something? Putting out ludicrous and stupid scare answers like that doesn't help.breezer said:
Your mission, should you choose to accept it - find me a domestic hob and a domestic oven which together draw enough current to cause a 10mm² to catch fire.
What is an oven + a hob, if not a cooker? If I bought an electric cooker, consisting of an oven and a hob and one set of terminals, got out my trusty hacksaw and wire cutters, and turned it into two appliances, why would it suddenly take any more current than before?andrew2022 said:
What knowledge do you have of the MCB protecting the cable? How do you know that an oven + separate hob will overload it and trip the breaker?
Your mission, should you choose to accept it - find me a domestic hob and a domestic oven of such ratings that the standard diversity calculations produce an answer of more than 40A (IMHO it is reasonable to assume that nobody would put in a 10mm² cable for anything less).
Diversity calculations are one thing - ratings are another. Are the socket outlets on CCUs rated at less than 13A? Everybody who makes/sells them describes them as "13A".breezer said:
If we change the figure in the diversity calculation from 5 to 13 for an oven, that allows us to have a hob of 15kW on a 40A breaker (15kW = 65.2A, 10 + (55.2 x 0.3) + 13 = 39.56)
Your mission, should you choose to accept it - find out what BS 4177: 1992 (1993). 'Specification for cooker control units' says about the rating of the built-in socket.
WHY??breezer said:shavvy said:And what is so wrong with connecting the hob to to the dedicated cooker curcuit
nothing, so long as it is just the hob on its own, which is not what this post started as, the poster wanted to connect the oven AND hob to the cooker cct, which is a no, no
It's interesting to read what the OSG has to say, in Table 1B "Allowances for diversity"
In the column headed "Purpose of final circuit.."
- 3. Cooking appliances 10 amperes +30%fl of connected cooking appliances in excess of 10 amperes...
Sharan17a wanted to know if he could get a junction box which would handle 10mm² cables, and you two went off on some mad tangent making claims which do not stand up to even a cursory analysis.
Sharan17a - if it's not too late, here's one:
and as ryanj can testify, it will easily accept 2 x 10mm² cables in one side.
As to whether you can connect both appliances to the same CCU, I'll ask the questions that nobody seems to have bothered themselves with so far.
1) What is the rating of the hob?
2) What is the rating of the oven?
3) What is the rating of the MCB on the circuit?
4) Will both appliances be within 2m of the CCU?
B
breezer
there is also the henly block but i didn't want to mention it
the reason i said no is the way he wants there is no sepeate isolation or cct protection
the other thing, assuming as most are the oven, if less than 3 kw how is he going to protect that, cant put it on 10mm cable with hob, it has only hob size fuse/ mcb.
you cant put it via an fcu becuse you physically cant get 2 10mm cables in an fcu.
sometimes it is best to have separate
the reason i said no is the way he wants there is no sepeate isolation or cct protection
the other thing, assuming as most are the oven, if less than 3 kw how is he going to protect that, cant put it on 10mm cable with hob, it has only hob size fuse/ mcb.
you cant put it via an fcu becuse you physically cant get 2 10mm cables in an fcu.
sometimes it is best to have separate
Ban all sheds:- that is the kind of help I was after. Very informative and educational - thankyou. I saw that 60a Junction box on the net before I started this post, so it's good to see you recommend it.
The oven is 2250-2400W, the induction hob is 6000W.
Cheers,
Steve.
The oven is 2250-2400W, the induction hob is 6000W.
Cheers,
Steve.
It was just a demo that ryanj did to show that you can get 2 x 10mm² into one terminal.notb665 said:
Ah - so not cables catching fire, then....breezer said:
Separate isolation is not essential.
Circuit protection? All the cables would be 10mm²....
Do integrated electric cookers have internal fuse(s) for the oven(s), or are they quite happy with the 40-50A MCB protecting the 10mm² cable supplying the one appliance?
No - but you can get 1 in:
[code:1]
===10mm²====[JB]====10mm²====[CCU]==={HOB}
||
||10mm²
||
[FCU]------1.5mm²-----{Oven}[/code:1]
That would also give you separate isolation
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