Ovens on cooker ccts

geoffsd:

gkenyon:

As we've recently discussed in another thread, it depends on the manufacturer's installation instructions - the manufacturer has a right to demand an appropriate circuit protective device is used to facilitate fault protection in their appliance - perhaps even the type and rating, e.g. I've heard of B25 mcb or RCBO being specifically stated by one manufacturer.

I disagree with that fundamental statement, but:

Happy to discuss, but you don't say why you disagree - it's a basic requirement in Chapter 13, i.e. a fundamental part of BS 7671  plain and simple

Why has the manufacturer the right to make products that cannot safely be connected to known standard circuits?

The appliances CAN be connected to a standard circuit (15, 16, 20 or 25 A radial) - just not one protected by a far higher rating of protective device. It's like saying "Not fair, I didn't know I couldn't supply my TV using a polo wrapper in place of the plug fuse".

Is the internal wiring of an oven any larger that that of a cooker?

It is not, so should a cooker be connected with two (or three) separate 16A circuits? If so, why in the UK do they come with the links between the two (or three) cooker terminals?

That is the manufacturer's design, NOT the designer of the electrical installation to consider.


It's a fundamental requirement of BS 7671 that the designer of the electrical installation considers manufacturer's instructions.

The internal wiring of an oven will safely cope with the fault current with a 32A OPD, therefore 433 and omission of overload protection may be applied.

433 applies to wiring of the fixed installation, not internal wiring in appliances.


As per previous thread ... we may not be talking about protecting wiring only, but of course ovens do include smaller wire than that used for the heating elements. The wiring for the heating elements might be OK for adiabatic at ambient temperatures of 20C, but the temperatures inside parts of the oven exceed this. Finally, BS 7671 doesn't contain tables for the wiring used inside ovens.


Why should we in the UK expect the rest of the world to capitulate to our vain hanging on to the 30/32 A ring final circuit, when mush of the rest of the world provides dedicated circuits for major items of fixed equipment. If we're not talking about an RFC, then what's the problem with swapping the B32 for a B16, B20 or B25 as necessary? (Of course from an appliance installers perspective , Part P becomes an issue, but that's merely another knot that's been tied for us that the manufacturer won't care about)

Do you think manufacturers of, say, a 70W television set have the right to demand a 300mA fuse?

 

geoffsd:

gkenyon:

As we've recently discussed in another thread, it depends on the manufacturer's installation instructions - the manufacturer has a right to demand an appropriate circuit protective device is used to facilitate fault protection in their appliance - perhaps even the type and rating, e.g. I've heard of B25 mcb or RCBO being specifically stated by one manufacturer.

I disagree with that fundamental statement, but:

Happy to discuss, but you don't say why you disagree - it's a basic requirement in Chapter 13, i.e. a fundamental part of BS 7671  plain and simple

Why has the manufacturer the right to make products that cannot safely be connected to known standard circuits?

The appliances CAN be connected to a standard circuit (15, 16, 20 or 25 A radial) - just not one protected by a far higher rating of protective device. It's like saying "Not fair, I didn't know I couldn't supply my TV using a polo wrapper in place of the plug fuse".

Is the internal wiring of an oven any larger that that of a cooker?

It is not, so should a cooker be connected with two (or three) separate 16A circuits? If so, why in the UK do they come with the links between the two (or three) cooker terminals?

That is the manufacturer's design, NOT the designer of the electrical installation to consider.


It's a fundamental requirement of BS 7671 that the designer of the electrical installation considers manufacturer's instructions.

The internal wiring of an oven will safely cope with the fault current with a 32A OPD, therefore 433 and omission of overload protection may be applied.

433 applies to wiring of the fixed installation, not internal wiring in appliances.


As per previous thread ... we may not be talking about protecting wiring only, but of course ovens do include smaller wire than that used for the heating elements. The wiring for the heating elements might be OK for adiabatic at ambient temperatures of 20C, but the temperatures inside parts of the oven exceed this. Finally, BS 7671 doesn't contain tables for the wiring used inside ovens.


Why should we in the UK expect the rest of the world to capitulate to our vain hanging on to the 30/32 A ring final circuit, when mush of the rest of the world provides dedicated circuits for major items of fixed equipment. If we're not talking about an RFC, then what's the problem with swapping the B32 for a B16, B20 or B25 as necessary? (Of course from an appliance installers perspective , Part P becomes an issue, but that's merely another knot that's been tied for us that the manufacturer won't care about)

Do you think manufacturers of, say, a 70W television set have the right to demand a 300mA fuse?