KWh calculating

[mac309]

I need to calculate the usage of a 3KW grill in KWh, sounds simple but because the grill thermostat controlled the load is not constant.

Is there a diversification factor percentage to take into account the time that the thermostatstat is in the off state?

[tony1941]

The short answer is "yes". Are you trying to determine the correct cable/circuit breaker sizes for this? The "On Site Guide" which is an offshoot of the IEE 16th Edition Wiring Regulations will give you all the info you need. To come up with a final answer, it's neccesary to consider allthe appliances on the circuit. Please give more details and I'll try to help.

[mac309]

Thanks for repying, the grill is a portable appliance and we are trying to determine the running costs for a customer over a period of time.

[heathfield]

If it's a portable appliance, can we take it that it's fitted with a normal three-pin plug?
If so, you could use a power monitor. Looking like a multi-way socket adaptor, it'll tell you what power has been used over a what period of time, and even what it costs if you enter the tariff.
See an example here.

[buildersmate]

He's not talking about cable diversity in the sense an electrician uses it for cable sizing, Tony.
I'd go with Heathfield's idea.

[tony1941]

AH! That easy!! Years ago I bought (from Exchange & Mart) an electric credit type meter which I then mounted on a board in the middle of a 13A extension lead. It has been incredibly useful for tracking down the cause of large electricity bill s over the years - a really good investment!
I got carried away by the apparent reference to diversity.

[Disco Fever]

Good idea Tony but if you leave the meter plugged in with no load on it it will still go round on it's own like all leccy meters in households....