watts = amps

[stephen_5126639]

Hi,the way i understand it the way to calculate the amps been used is:the watts of a apliance devided by the voltage,so if i had say a 2kw heater plus a further 1kw water heater i would not be able to use the apliances on a 10 amp site,has any one any idea where i could download a chart giving me an idea of what caravan apliances use " please do tell me if i am wrong hear but i am new to caravaning,steve

 

[David_5127637]

What you say is right for DC electric calculations but is a little more complex for AC mains because of power factor. The W/V=A is a fair indicator though.

Your 10 amp supply is nearly maxed out with a 2 kw loading. Be careful of electric kettles some of which can have high wattage and check the loading label on the appliance. If you are running an electric heater it is a fair assumption that putting on the electric kettle will trip your 10 amp MCB breaker.

 

[rob_jax]

Hi,

You should be aware of a few things:

1. The "input" watt rating on an appliance is the maximum power required to run the device - so the watt rating on something like a home fridge only hits the maximum input when the compressor is running.

But this is a safe indication for you to use of the maximum power required.

2. The "output" watt rating on an appliance - like a 50 watt stereo or 700 watt microwave is not the input power required to run the appliance (because of inefficiencies in converting electricity into microwaves, and all the other electrical stuff in the oven).

So a 700 watt microwave will actually be closer to an input power of 1000 watts.

The data label on the appliance will have the maximum input power listed - use this in your calculations.

1000 watts is very close to 4.25 amps at mains voltages.

So a 2 kW heater plus a 1 kW water heater needs 12.75 amps (more than you can draw from a 10 amp supply) - this is slightly complicated by the fact that these are not "always on" but the heaters only draws power when needed - but at some time both heaters will be on - and the trip will switch your caravan off.

And don't forget your caravan fridge which draws a constant (220 watt) or 1 amp from the power pole all the time.

Robert

 

[stephen_5126639]

Hi guyes,well thanks for your info " not that i would use a electric heater as i have a exelent carver gas heater,its just in case of emergencies etc,though i do use a electric kettle maybe i should use the gas one,though i am looking at fitting a electric water heater,steve

 

[RayS]

If you are a CC member there is a guide to which appliance takes what power in the "yellow pages" of the Members Handbook.

It's all a bit approximate, as some appliances have a high inrush current on switching on, which can trip the breakers even though theoretically things should be o.k.

Conversely, some site breakers seem to be quite generously rated, and i have seen sites state 6 amps when the breakers were in fact 10.

 

[stephen_5126639]

If you are a CC member there is a guide to which appliance takes what power in the "yellow pages" of the Members Handbook.

It's all a bit approximate, as some appliances have a high inrush current on switching on, which can trip the breakers even though theoretically things should be o.k.

Conversely, some site breakers seem to be quite generously rated, and i have seen sites state 6 amps when the breakers were in fact 10.

Hi, i am not a member of cc however i am joining as we are going away with the van next month and the fee is reduced by