Browse Forums General Discussion 1 Dec 08, 2011 9:53 am Does anyone know why I would be getting 100volts at a switch in my place instead of 240? It is for a pneumatic switch to control a pump that runs a water heater. The heater is right down the back of the house and the switch is in the kitchen. The electrician had a quick look and is coming back when he can to inspect it, but I can't figure out why. The switch is linked to the pump via twin 2.5 switch wire, comes back from the power point at the pump on red which has 240 and terminates at the hard active terminal. Through the switch and returning on the white it only has 100 volts. Could this be voltage drop, as it is at least 20 metres plus, also the house is 3 phase, does this come into it? Obviously all work will be carried out by a qualified A grade. Chris Re: only getting 100 volts instead of 240 2Dec 08, 2011 9:42 pm Hi Chris Not meaning to be offensive, but let your electrician work it out. If he needs you to help him out by asking questions on a forum, time to get a new electrician. You will be pushing the proverbial up the hill to find someone to give you electrical fault finding advice on a forum. AJ Re: only getting 100 volts instead of 240 3Dec 09, 2011 8:04 am Firstly, it's not a voltage drop along the 20 metres of cable. Twin 2.5 mm diameter wire has a resistance of 0.13 ohms (2 runs of 20 m), which means you would need to draw 1080 Amps to get the voltage drop you are seeing!!! So, we're down to two possibilites. Firstly, there is a high resitance point somewhere. This is also unlikely since such poiont, given the currents involved, would get very hot and would be obvious. Also, it would deteriorate quickly due to the self heating. Secondly, your neutral is not well terminated at the house (or somewhere along the line). This would mean that your neutral can "float" between the phases and you can get unusual voltages. If this is the case then all the voltages in your house would be unusual. Also the voltages would vary as different loads are turned of and on. So, unless I've got the wrong picture about your circuit, I wouild put my money on a poorly terminated neutral leading into the house. Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: only getting 100 volts instead of 240 4Dec 09, 2011 9:08 am Thank you Aj and Cas. Yes Aj he hasn't looked at it yet, he was here for another job (ixl tactic) and I asked him at the end to look at it. He told me it could be a few things but he was leaving and I have him booked to come back after christmas. He did mention Neutral problems so it could be what you are saying Cas, but I don't fully understand it. I am just curious as I like to have some idea of what is happening in my house, it's like when you take your car to the mechanic for an oil change and he tells you you need a completely new engine, just want to be in some position of knowledge and not allow myself to be ripped off too easily. So Aj you say using this forum is not ideal for fault finding, do you know a good site/forum that is? I like to spend spare time reading up on things like this. Cas do you think the electrician will need to do major work to fix the neutral problem/s? Do you think it would be in the switch board? Thanks Re: only getting 100 volts instead of 240 6Dec 09, 2011 8:49 pm Hi Chris, I could be wrong, but personally I believe that giving advice whether online or in any other form can lead to trouble. For example, a person has been killed or seriously injured playing with his electrical service. In the investigation, his wife mentions to the police that he was given advice on a forum. This advice could be said to have contributed to the injury/death. I would not like to be defending that one in a court of law. Sorry, but this is why I WILL NOT give electrical advice to people which I don't know their particular skill level. Other trades can be a different story, plumbing for example at worst is going to cause a bit of water damage, not a death. AJ Re: only getting 100 volts instead of 240 7Dec 09, 2011 9:49 pm Thank you for your replies. I have no intention of poking around somewhere where I shouldn't, I just like to know what he is explaining is the truth and he has fixed it and I won't need to constantly have it repaired. So it is possible other points in the house are like that too then i guess, perhaps he should check it out. Thanks again That sucks! Hope it all works out. Good to move away from steel anyway for all your reasons, but it's also thermally poor. 16 17887 AFAIK, flashing is a minimum standard. Out of curiosity is your window glass stamped with AS requirements in any of the corners of each pane? Im almost certan if theyre… 2 6278 As is per usual for many of the past failed RWH regulations, it is probably traceable to a bureaucrat who's ego overrode the need to seek the appropriate expert… 1 1021 |