220v. 230v, 240v, 250v?

[John-SJW]

I saw an oven that was rated at 3,100 watts. Now most would say that cannot be fitted on final ring circuit as rule of thumb. But:
3,100 watts draws amps of:
14.09 amps @ 220v
13.47 amps @ 230v
12.91 amps @ 240v
12.4 amps @ 250v

If the installation is 240v or 250v then it safely inside the 13 amp of a final ring circuit.

The question is, and the regs aficionados can help here, what is the voltage that should be used to assess, as maybe the voltage will vary in an installation over the years.

 

[John-SJW]

Agree, but I think you are still misunderstanding the relationship, if the voltage drops, so does the current, the real issue is if the voltage increases

I got that. I wanted to know if there is a set voltage used, as we have variable voltage from premises to premises in the UK.

 

[LastManOnline]

I saw an oven that was rated at 3,100 watts.

Did oven come with a lead and plugtop attached?

 

[John-SJW]

Returning to the subject of the cooking appliance. If the power rating is given at 230V it will take rated current at 230V and more at 240V. If the power rating is given at 240V it will take rated current at 240V and less at 230V. Many heating elements only deliver rated power at their highest rated voltage, making that the worst case for current.

I think I have an answer. It is rated 220-230v. A rating of 220v, find resistance then apply that resistance to a 230v supply to get worse case of those two voltages.

 

[LastManOnline]

I got that. I wanted to know if there is a set voltage used, as we have variable voltage from premises to premises in the UK.

If as you say it was a "continental oven", then 230v is the norm there. It would be connected to a socket via an unfused plugtop to a 16 amp radial circuit

 

[John-SJW]

Did oven come with a lead and plugtop attached?

I do not know.

 

[John-SJW]

If as you say it was a "continental oven", then 230v is the norm there. It would be connected to a socket via an unfused plugtop to a 16 amp radial circuit

More like a 20 amp circuit to give some margin.

 

[littlespark]

I wouldn’t worry about it too much....

As they say “resistance is futile”

?

 

[catdog1121]

Are these Neff ovens by any chance?

Two things:

1. I believe any load above 2kw should not be placed on a ring final circuit unless it is a lightly used circuit, the reason for this is that you overload one leg of the ring, unless you can ensure you are putting the load in the middle.

2. Check the instructions as most of these ovens state they need to be on a 16A circuit, this can often mean you need a separate circuit for the oven and hob. It used to be that you could rely on the oven not being likely to overload but these new ovens have all sorts of features.. You should follow the manufacturers instructions.

 

[LastManOnline]

More like a 20 amp circuit to give some margin.

Not necessary. A 3 kw oven is an entirely different prospect to a 3kw space heater. The oven needs to heat a space of less than a square meter.The space heater, many times more than that and hence works much harder

 

[telectrix]

Not necessary. A 3 kw oven is an entirely different prospect to a 3kw space heater. The oven needs to heat a space of less than a square meter.The space heater, many times more than that and hence works much harder

but... In Space, no-one can hear you scream.

 

[Vortigern]

One thing occurs is that a 3+Kw oven will probably come with a 2.5mm² lead so that wont be going into a plug. My take is that Appendix 2 suggests 230v for calculation as the nominal voltage. I know of course that 240v + is the real voltage we are dealing with. Put the fact that 3+Kw on a spur very often leads to meltdown of the spur a double pole switch is better. Then you would have to have it on separate circuit. Which is after all (arguably) best practice. Then of course finally diversity would bring the oven load down to about 11.5 amps. So take your pick.

 

[MJPD29]

More like a 20 amp circuit to give some margin.

No, 16 is correct.

 

[John-SJW]

Then of course finally diversity would bring the oven load down to about 11.5 amps. So take your pick.

Good point.

 

[John-SJW]

One thing occurs is that a 3+Kw oven will probably come with a 2.5mm² lead so that wont be going into a plug. My take is that Appendix 2 suggests 230v for calculation as the nominal voltage. I know of course that 240v + is the real voltage we are dealing with. Put the fact that 3+Kw on a spur very often leads to meltdown of the spur a double pole switch is better. Then you would have to have it on separate circuit. Which is after all (arguably) best practice. Then of course finally diversity would bring the oven load down to about 11.5 amps. So take your pick.

I have seen ovens of 3-3.5kW and induction hobs above them, on the same 6mm cable, 40A circuit, treating the two as one large cooker. Diversity can come in, in that case.

Light on electrical connection. 1.5mm lead.

The oven I looked at was a Smeg combination oven of a built-in 1,000w microwave and oven. The microwave and oven can be on at the same time.

 

[LastManOnline]

One thing occurs is that a 3+Kw oven will probably come with a 2.5mm² lead so that wont be going into a plug.

My "Morphy Richards" kettle is 3kw.It has a lead that is max 3x1.5mm (but probably 1mm. Moulded plugtop so can't check) .Before energy saving appliances came on the scene it was normal to have washing machines, driers etc up to 3.5 kw, all connected with 13amp plugs and usually 1.5 flex. A 1.5mm flex can comfortably handle a continuous current of 13 amp (and above). The key difference between appliances of the same wattage is whether they are designed to be used intermittently (kettle) or in a more sustained way (space heater). A sustained load should really have its own circuit.