# What's the standard for specifying power and voltage characteristics of domestic appliances?

I'm planning to buy a space heater with the following electrical specifications:

• Power : 2000 W
• Operating Voltage : 220-240 V

Many of the reviews say that the heater requires a 15 A socket to work efficiently, whereas most of regular sockets have 5 A capacity.

In India, we get 230 V at 50 Hz.

I'm confused about the power specification. Is it root mean square (RMS) power or peak power?

`P = V * I`

If we assume 2000 W as peak power, the current capacity for socket comes out to be:

`I = 2000 / 230 ~ 8.7 A`

However, if you take 2000 W as RMS power, the current capacity for socket comes out to be:

`I = 2000 / (230 * 0.707) ~ 12.3 A`

What's the standard for specifying power and voltage characteristics of domestic appliances?

I'm sure that the voltage specified is peak voltage, but I'm not sure whether the power specified is peak power or RMS power.

• Mains voltage is usually RMS. So your 230 V is RMS. See Wikipedia Feb 4, 2015 at 10:12
• @RedGrittyBrick So the current capacity for the socket would be ~ `8.7 A`, is it? In that case, this shouldn't work with socket types C and D with 5 A capacity. Feb 4, 2015 at 10:24
• Correct. 2000 / 230 = 8.7 A. So you cannot connect this to a 5A outlet. Feb 4, 2015 at 10:24

What's the standard for specifying power and voltage characteristics of domestic appliances?

RMS is used to make calculations easier for consumers.

Some UPS devices express power as VA, but most consumer appliances used in homes specify Watts.

the voltage specified is peak voltage

RMS, not peak.

I haven't been there and measured it but I am sure the mains voltage in India is near 230V RMS (I would guess it is nominally 240 V RMS but I expect in some locations the electric power companies fail to keep voltage levels up because demand exceeds what their plant can supply)

the heater requires a 15 A socket to work efficiently

No, it requires a 15A socket to work safely. This isn't about efficiency.

A 2000 W appliance is likely to present a too-low resistance to a 5A outlet and will likely cause the wiring inside the walls to overheat and may set fire to your home. The sockets themselves may also overheat and be damaged, possibly presenting electrocution hazards.

If Indian homes are wired to the equivalent of BS546, you only have a choice of 5A or 15A outlets, you should choose a 15A outlet for a 2000W appliance.