Electric or mixer shower?

[Karen2005]

I bought a 10.5kw electric shower to be installed after I had my flat re-wired, but my electrician told me that the power coming into the flat wasn't sufficient for such a powerful shower. I think there are 60amps of power coming into the flat and the electrician had installed a 6mm cable before realising that I had bought a 10.5kw shower and that it wouldn't be suitable. I have obviously now taken the shower back, but now I am in a dilemma as to what sort of shower to get.

I think I could only get a 7.5kw shower because of the 60amps coming into the flat, but I am worried that it won't be powerful enough (I can't get a pump added because I have a combi boiler).

Would you recommend going for a 7.5kw electric shower, or go for a mixer one instead? Which would be more powerful? Because of the combi boiler, all water comes off the mains and there are no water tanks.

Thanks!

[qapmoc]

You are slightly confused about the power that a shower uses. The power rating is how much the shower will heat up the water, it's got nothing to do with pressure or water flow etc... except -
1. The more water you try to heat the more power you will need. This will get worse if you add a pump which will increase the flow rate. So if your incoming water pressure is not very high (ie the flow rate is low) you will need less power..This also applies if you keep the shower itself set to a lower flow setting.
2. The colder the incoming water is the more power you will need to heat it. So if your incoming water is not very cold (might not be if it's a flat) you will need less power.

Unfortunately this info is not much help for you, because nobody can tell you what minimum size shower will be OK without knowing your water pressure and incoming water temperature ! But in reality a lower powered shower should be usable, you would just have to reduce the water flow until it gets hot enough. Really you need someone with experience of your exact location to assist you.

[Karen2005]

Thanks for your answer qapmoc. The power ratings etc make much more sense now. I didn't think something as simple as choosing a shower would be so complicated!

[stanleyman]

A combination boiler is ideal for supplying hot water to a mixer shower and will heat far more water than an electricly heated shower unit. The water pressure is supplied by the incoming water mains and no pump is required. You will of course need a hot and cold supply for mixing to the right temperature.