3500w Water Heater On 2.5mm^2 Wire ?

[painless]

Hello All,

I had already run the cable when I picked up the heater.

The instructions say to use 4mm cable on a 20Amp breaker.

I had guessed using Crossy's guide that 2.5 would be ok.

No fault directed at Crossy. I think he has done a sterling job.

Anyway some advice from the experts would be nice.

Do I really need to rip it all out and put the 4mm in?

Cheerio

Blair

[WilliamTarmby]

I wouldn't rip it out, 2.5mm should take over 5kw/20+ amps (nearer 7KW absolute max) However, you will be lucky if your mains supply will will deliver that anyway as the electric here is shit at the best of times.

I would ensure you are well grounded, you have regularly tested the breakers, and don't have anything conductive in the shower, you will then be about 300% more safe than the average Thai...besides, can you actually GET 4mm here? Copper I mean, not their aluminium or "plated" crap? I think that the safety side with breakers etc. would be a wiser move than to rip out your existing wiring.

[Crossy]

Pretty much agree with Bill^^^, yes you can get real copper here.

3500W @ 220V = 16A, well within the capabilities of 2.5mm2 on a 20A breaker. Use what you've installed with no problem, your only issue could be on a long run (25m+) with volt drop reducing the power available, certainly no hazard though.

That said I would have run 4mm2 for a water heater anyway, in case the water wasn't hot enough. But hindsight is always 20:20

Edited October 1, 2008 by Crossy

[painless]

Yes I would have thought so.

Well that is good I will just finish the install and leave it at that.

Thanks again.

[mdechgan]

What is the distance between the heater and main breaker or power source?

With 2.5mm you can go up to 50M without more than a 5% voltage drop.

[dotcom]

Your pushing it painless but I think you will be fine. 20 amp breaker - yes.