I recently had my solar hot water system replaced. The old one had a 1.8kw heater and the new one has a 2.4kw. The installers used the old heater wiring. Since then the 10amp switch for the heater failed. It obviously got hot and fell apart. My concern is that the wiring may also be under rated. I'm in Australia so it has to carry 10A at 240V. My thought is that 10A wiring would have been good for the old heater and probably that's what was installed. Comments please.
Secondly, how would I approach a contractor for an opinion without giving them an open invitation to replace the lot ?
At 240 volts, the 1.8Kw water heater would draw 7.5 Amps, and the 2.4Kw heater would draw 10 Amps. To an appliance like this, a #12 guage wire would be the least that would be installed, although theoretically, a #14 guage wire would be sufficient.
Presuming the installer knew what he was doing I'd say you had nothing more serious than loose connection in the switch, try a new one but check it for temperature when the heater is running
What wire size do you have on the existing hot water heater? Under the NEC of the USA #14 wire can handle 10A, but it's not a bad idea in this case to go to the next wire size up if that's the problem. I can't imagine you guys using anything below #14 wire. That wouldn't be safe. So it shouldn't be your wire size.
How do you know it's a ten amp switch?
I would replace the switch myself if I were you. Let's start simple. A switch isn't like a fuse. It can handle more amps for a longer period of time without faulting. Though it may get hot to the touch. As long as it wasn't hot I would replace it with no problem. If you do replace it see if it gets hot to the touch, then you know there's a problem.
An electrician could put an amprobe up to the wire and see what you are drawing for real.
In America I'd call 3 contractors up for their free estimate (if that's the way AU works) and opinion and talk to each one. If all three have different opinions then you have some problems, because you don't know which one's telling you the truth.
When they come out for an estimate, you can ask if they could replace your switch (or you could do it), as long as they have one handy, which they might if they have a truck and are a small outfit. See what that does. Pay them their (US) $35 or so dollars and hope for the best. Then work your way up from there. They'd love to make a buck while out on an estimate. Don't be shy about this.
When they come out have them explain why you need to have the electrical wire replaced, and try to get a second opinion, if that's what they want. Write everything down and don't trust anyone. Approach like you would a military battle. Sometimes the best offer turns out to be the worst and the worst offer the best. If the bidder is the electrician, the more power you have over your negotiations.
Good luck Down Under. Up Over here ain't doin' so great.
Thanks Zzzap, I've replaced the switch myself and will start the estimates next week. I've been a bit slack with checking the wire gauge, 30°C+ here and sunny, I hear it's a bit cooler over your way.
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