My friend's boiler stopped working.
British Gas came and established boiler was getting 180 volts from its main supply and the kitchen sockets on the same circuit were also 180 volts.
There's been some suspected dodgyness in the consumer unit in the past I seem to remember. We'll be getting an electrician in to look at it but I wondered what people though might be the cause?
Loose wire in a terminal? But if you have to ask you probably don't have the experience to safely test it and I *strongly* suggest leaving it strictly alone, and not plugging anything into that circuit, until the electrician comes.
Suggests pretty dodgy wiring. Even a few amps dropping 60 volts somewhere will be generating quite a bit of heat at the fault site. That's when you have some load on that circuit, obviously. What circuit is it on? I guess you *could* run a boiler off a lighting circuit (although I don't think I would, unless there was a good reason).
Murmansk formulated on Saturday :
Alternatively, it could be that their meter might have been faulty and giving wrong readings. 180v on a circuit would be very noticeable for other things in use on the same circuit. Standard practice when such an unexpected value is found, is to double check it with a second meter.
Or the meter was doing just what it is designed to do so but the gasperson wasn't well trained. 180V from L to N or L to earth is a likely reading on a standard high impedance multimeter picking up the induced voltage if L is disconnected at the CU. fairly good clue is that the boiler is completely dead. Connect a normal (incandescent) light bulb into the socket (use any table lamp) and it is likely the bulb will not light and the 180V will drop to nothing.
Y plan controls also generate odd voltages fwiw
NT
Or some dodgy test gear with a nearly flat battery?
Yes, as Harry said.
+1
Yes, I get 90-odd volts on my boiler supply when it is turned off at the double-pole isolator (upstairs with the controls and a lengthy run downstairs and to the back of the house to the boiler). Unfortunately, there is nothing else on that supply for me to use to pull it down and it hurts if you accidentally touch it!
SteveW
Only if there is no significant load. If this was not checked with some sort of load then I agree. Though a stable 180v is unusual I think.
You don't mention whether you tested the voltage on other circuits. Can you confirm that you were getting 230-ish volts elsewhere?
Many years ago I had a voltage problem which was traced to a connection in a pole transformer a few metres away from the house. (Rural area: overhead cables) In those days, the incandescent bulbs gave away the problem at once but I wonder it it would have been so easy to identify with so much mains equipment nowadays being designed to run on anything from 100v up?
Nick
All of those scenarios are perfectly good reasons for the OP's friend's
180v problem. Unfortunately, he also mentioned that all the kitchen sockets from which the boiler mains supply was spurred off were also only showing this 180v reading. If these statements are true, electric kettles will take noticeably longer to boil a pint of water, toasters will fail to toast bread and their elements will also be very noticeably dim, as would a table lamp with an incandescent lamp fitted.Indeed, even if the mains supply had been dropping gradually in voltage over a matter of weeks, I can't see how the OP's friend could have failed to see other symptoms such as a desktop PC no longer powering up (their PSUs kick in at 186volt and drop out at 185 volt[1]) or the fridge and/or freezer failing or even bursting into flames!
The low voltage 'reading' looks more like a measurement error than a supply voltage problem in my considered opinion.
[1] A memorable test using a variac transformer done by PC Pro magazine's review team two decades or so back on an office full of various desktop machines to test their susceptibility to mains brown out events. The result was remarkably consistent 185v 'drop out' and a 186v cut in values for all the machines they were able to test.
No, the opposite in fact. A cheap 'n' cheerful DMM still works even when the "Bat" indicator is being displayed. Fortuitously, the effect of a "nearly flat battery" on the A2D converter's internal voltage reference is to reduce it which inflates the digital values it produces, leading to higher than correct readings being displayed.
It's fortuitous in that it's safer to mislead the user into thinking they're testing a higher voltage (or current) than is safe to work with, rather than misleading the user into thinking the opposite, leaving the user to engage brain and verify that the "Bat" (low) indicator hasn't surreptitiously activated its alarm (the "Bat" indicator is all too easily overlooked on the cheaper DMMs' smaller display panels).
Getting back to the topic of 180v on a nominally 240v supply[1], this, if it's a consistent value even with a kettle plugged in and out of one of the effected kitchen sockets, would seem more like a voltage regulator fault in the substation or, in a rural location, a pole top transformer.
[1] Forget about the "notional" 'harmonised 230v', check the voltage marked on any mains voltage incandescent GLS lamps you have in the house. These have to be specified to within +/- 5% of the actual supply voltage in order to meet their rated life and brightness specifications making them a trustworthy indicator of the actual mains voltage each customer in your locality is 'supposed' to be receiving.
True but not at the the mains connection.
Exactly if serious current has been drawn its probably got very hot somewhere and charred or melted the innards. In fact I'm surprised nobody has smelled it by now if its actually in the property. We had a circuit breaker go this way, like a resistor, and it smelled like rotting unmentionables mixed with burned plastic. Brian
Well if a kettle is still boiling then the supply must be at 180V[1]. If a kettle does not boil then the circuit is dead.
[1] I doubt that a loose connection would drop 50V without been noticed by now and plugging a kettle in would drop it by even more.The OP could of course get his mate to boil a kettle in the kitchen at the socket [2] that was showing 180V with a known amount of cold water, time it and then repeat this on a different circuit. If there is a difference in time then [1] is incorrect and there is a loose connection dropping 50V.
[2] Some of the kitchen sockets may be fine - it has to be boiled at the one claimed to be at 180V.
I was questioning whether the 'engineer' had made a mistake in that respect. More likely not but also possible.
Peter Parry has brought this to us :
+1
But it could be outside the property. In my in-laws case it was a bad joint on the pole outside. A gentle tap with an insulated pole and the wire fell off.
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