Using pre installed cooker circuit for 13amp or 16amp oven.

[SUNRAY]

Don’t be so ungrateful.

Ungrateful?????
For making a totally irrelevant and stupid comment?
If OP hadn't posted here I wouldn't have seen it!
Equally if OP hadn't poste on SF site then A.N. Other wouldn't see it.

Either way OP may not have got an ideal suggestion. Criticising the decision to ask the question in 2 places is simply stupid, even uneducated.

 

[SUNRAY]

Don’t be so ungrateful.

Ungrateful?????
For making a totally irrelevant and stupid comment?
If OP hadn't posted here I wouldn't have seen it!
Equally if OP hadn't poste on SF site then A.N. Other wouldn't see it.

Either way OP may not have got an ideal suggestion. Criticising the decision to ask the question in 2 places is simply stupid, even uneducated.

 

[SUNRAY]

Ovens normally come with cable already fitted. Use it.

normally Really??? The last 3 I've fitted had a terminal box on the back, no cable

It can be connected straight into the cooker plate. 45 amps is its max rating, it will still work at lower currents. The 32 amp MCB is OK. The oven cannot draw more than its max rating.

That is until it developes a fault and the cable rated for 16A is being asked to carry45A. The 32A over current device will happily pass such current for 3 hours.

That doesn't sound like good circuit design to me but according to winston1 it's perfectly safe and acceplable.

 

[EFLImpudence]

That is until it developes a fault and the cable rated for 16A is being asked to carry45A.

How will that happen?

 

[SUNRAY]

How will that happen?

How will what happen?

 

[EFLImpudence]

How will what happen?

it developes a fault and the cable rated for 16A is being asked to carry45A.

 

[SUNRAY]

How will what happen?

That is until it developes a fault and the cable rated for 16A is being asked to carry45A.

Which element are you questioning?

 

[EFLImpudence]

All of them.

How will the oven develop a fault and ask the 16A cable to carry 45A?

 

[SUNRAY]

All of them.

How will the oven develop a fault and ask the 16A cable to carry 45A?

It's called a fault... when things go wrong. I take it you have heard of faults?

 

[EFLImpudence]

Not ones which cause an oven to develop a fault and ask the 16A cable to carry 45A for three hours.

 

[SUNRAY]

Not ones which cause an oven to develop a fault and ask the 16A cable to carry 45A for three hours.

I take it you've not worked on many heating devices then.

Enclosed elements develop short circuits between the current carrying part and the earthed outer. Just before Christmas I changed a 1.5KW element in a heater battery which was tripping its 10A MCB.

And I've had several immersion heaters which have developed faults and operated the OCD

 

[JohnW2]

Enclosed elements develop short circuits between the current carrying part and the earthed outer. Just before Christmas I changed a 1.5KW element in a heater battery which was tripping its 10A MCB.

Don't you think it would have tripped a, say, 32A MCB?

Kind Regards, John

 

[SUNRAY]

Don't you think it would have tripped a, say, 32A MCB?

Kind Regards, John

I truthfully don't know. I did'nt take note of the resistance but if the short circuit occurred at ¼ of the length of the element it would be 6KW which would not trip a 32A in a month of sundays, whether the element would fail in 3 hours I wouldn't put money on.

EDIT: But that doesn't change the fact that a 1.5KW could justabout be wired with 0.75mm² wire which would not like to be running at 32A

 

[JohnW2]

I truthfully don't know. I did'nt take note of the resistance but if the short circuit occurred at ¼ of the length of the element it would be 6KW which would not trip a 32A in a month of sundays, whether the element would fail in 3 hours I wouldn't put money on.

Yep.

This is, of course, a situation in which RCD protection would solve the problem, whereupon the rating of the OPD would become essentially irrelevant. It is all-but-inconceivable that an L-N fault 'of appreciable impedance' (i.e too high impedance to magnetically trip a MCB) could arise in/around a heating element, so any such fault would inevitably be L-E, and an RCD would immediately respond appropriately.

Kind Regards, John

 

[winston1]

I take it you've not worked on many heating devices then.

Enclosed elements develop short circuits between the current carrying part and the earthed outer.

So a fault current of no more than 30mA then the RCD trips. Not 45 amps.