240v LIVE boiler

[Backboiler]

While safety check/servicing a Glow-worm BBU today I discovered there was no fused spare to isolate the boiler. The customer was recording his favourite program, and requested I didn't switch off the electric, so I switched off the demand for heating and water at the programmer. I proceeded and took the risk. I checked the boiler with my voltstick and confirmed it was dead. I disconnected the gas connection at the 3 way gas tap and received a nasty elecrtic shock. After picking myself up from the recoil, I tested the boiler with my voltstick and the entire boiler was live!. Sod the tv program, I insisted on isolating the electric supply at the fusebox. Out of curiosity I reconnected the gas pipe, restored the electric supply and tested the boiler again...... No voltage, it was dead. Does this mean the equipotential bonding is not present some where? Needless to say the gas pipe is bonded at the meter having checked it during the TT. I continued the my work with the power off. I did notice that the 240v supply to the boiler had what appeared to be a connection taped with insulation tape. I intend writing a report about this to the letting agent. Can anyone throw some light on why the boiler was live with the gas bipe dosconnected and yet no breakers had tripped? I need some ammunition for my report. Thanks in advance

 

[kirkgas]

it could have a permanent live to run the lights on the fire, are you mad doing this kind of work with the power on? sod the telly programme, get the power off at a suitable fuse, isolator or at the main fuse board, you could have died, the regs dont require a fused spur at the back boiler, but they do require an iso somewhere, 99% of old BBU systems have a fused spur beside the programmer, or in beside the pump and zone valves at the cylinder

 

[tamz]

Get it recorded on your paperwork to be checked by an electrician. Possibly there is a burnt cable or dodgy connection which you have been unlucky enough to have learned a sore lesson and have been lucky.
The earth wire is the route of least resistance and was doing it's job until you disconnected it and touched it when you became the route. You should have switched it off and labeled as AR or ID.
Never place too much trust in a volt stick.

 

[kirkgas]

Get it recorded on your paperwork to be checked by an electrician. Possibly there is a burnt cable or dodgy connection which you have been unlucky enough to have learned a sore lesson and have been lucky.
The earth wire is the route of least resistance and was doing it's job until you disconnected it and touched it when you became the route. You should have switched it off and labeled as AR or ID.
Never place too much trust in a volt stick.

i use a volt stick all the time, but i use it to prove the power is on not off, ie if the boiler wont fire i run my volt stick up the cable and if it lights up i know the power is on so i dont need to go back the way to check fuse or fuse board, however if the volt stick doesnt light up i dont take that as being guaranteed that the power is off, safe isloation is easy if you follow a logical check ie, start with the power on, check it is on using test lamp, switch it off confirm it is off (this means you are controlling where it goes off) then recheck your test lamp on a known live supply, this also proves you are in control of isloating the power, if you use test lamps and put the power off (or think you have by say turning timer to timed instead of off), test lamp will say it is dead then in 15mins when the heating is due to come on it will zap you)

 

[stevie]

Sounds like a fault that still needs sorting , there seems to L-E fault on the boiler or pipe work , this could well still be there and dangerous as it indicates that the earth bonding isn't doing it's job / connected at the f/board

 

[Backboiler]

Yes I know Kirk, hands up I must be mad. I am aware of the dangers but I took a risk and I learned a huge lesson. A bit like marriage I suppose. The boiler fire (Sahara) had no lights so I reckon a stray wire may be the cause. I didn't ID or AR it because in my opinion it does not contravene the gas regs.

 

[GasmanxxxR1]

Im glad you lived to tell the tale. I hope this experience will lead you to prove positive isolation on every occasion. Remember you need to go home to your wife and kids at the end of the day.

 

[stevie]

All Earth cables lay dormant , they are a safety feature , so if any form of an earthing system becomes live ( including pipe work ) and the fuse dosnt react there are problems.. Advise them to get a spark in ASAP

 

[tamz]

The AR or ID for this type of incident is not stated or covered under the giusp but a risk assessment should have been carried out which would clearly state there was a risk to life and as such the appliance disconnected until further investigation was carried out. Sometimes you have to think outside the box.

 

[villa_tom]

An electric shock is not a nice experiance I was once working on a Halstead best 40 and got a right fright, got thrown off my ladder and cut my arm right open and burnt my fingers. I learny my lesson though and always turn the power off on every boiler now, but atleast I learnt from it and so have you mate.

I would agree with what tamz saya as far as ID/AR goes. I'd just go back and AR it and advise the customer. I dish out NTCS and AR's for fun sometimes if I'm unsure on something and its not covered in the unsafe sits book. The way I see it is that no one can get on your back for being over cautious but if you leave something naughty behind and don't raise it with the customer then your leaving yourself wide open, you can always retract your warning notice but you can't stick one in post job.

 

[AWheating]

safe isloation is easy if you follow a logical check ie, start with the power on, check it is on using test lamp, switch it off confirm it is off (this means you are controlling where it goes off) then recheck your test lamp on a known live supply, this also proves you are in control of isloating the power, if you use test lamps and put the power off (or think you have by say turning timer to timed instead of off), test lamp will say it is dead then in 15mins when the heating is due to come on it will zap you)

safe isolation should not include a live test, there is no need to risk opening up covers with power on. You should isolate the supply before you start using your voltage tester and then use a known supply to prove the tester works correctly after wards.

 

[GrahamM]

Sorry to say Alan but directly relating to gas regs or not this appliance is AT RISK at the very least and should have been left as such. You have a duty to protect life and property and in my opinion you were neglectful of this here. This appliance is potentially dangerous. The next person that touches it may not be so lucky.
Every electricity supplied appliance (boilers included) should have a means of direct, safe isolation. Ideally a fused spur. If this is not present this in itself is a safety risk. Most of the MI's will state the appliance must be protected by a 3AMP fuse. If you cannot confirm safe isolation of the appliance before working on it you are taking a risk.

We all get complacent at times and I got caught out a few months back. Cant recall exact boiler (think was a 12 year old Worcester 240 RSF) I fired up the boiler and hit the fused spur beside it. Gas valve shut off and lights went out. Thinking appliance safe I started to work on appliance unbeknown to me there was a second live feed. Like yourself I got a bit of a wake up call. I took a marker to the spur and wrote "2 LIVE FEEDS" and issued the customer with a safety notice.

 

[gasmarc]

you never stop learning in this game and i like to think I am carefull working on live boilers but will always check its properly isolated. I went to a job before for a sparks and i managed to get the boiler to fire up for a few seconds and then spent the next 3 hours trying to fix it with no joy and on top of this I managed to get an electric shock as the sparks said he had turned the power off which he had not, So a lesson to be learned there for me

 

[kirkgas]

safe isolation should not include a live test, there is no need to risk opening up covers with power on. You should isolate the supply before you start using your voltage tester and then use a known supply to prove the tester works correctly after wards.

sorry AW you are confusing me, what have i said that is any different to your comment, you check the supply is on, you turn it off, you check it is off then you recheck your test lamp on a known live supply, i didnt say you open up covers with the power on

 

[gasmarc]

I would advise anyone never to open electrics with the power on , you could get deaded very easily

 

[Pssst]

There is obviously some current leakage going on in the house somewhere. Whilst the gas supply was connected to the boiler,presumably the boiler was touchable? This is because the boiler and gas supply are at the same potential with respect to Earth.

You disconnected the gas pipe...now the pipe and the boiler metal lump and its connections are at different potentials..the potential on one side has risen to such a level that it gave you a shock..

This illustrates the need to use temp continuity bonds when cutting into pipes..its the same principle..

Theoretically,you should have been all right working on the boiler..not ideal..but there seems to be a fault ondition which needs checking out by an electrician in this case.

 

[GQuigley67]

I have had a few electric shocks, one from 110v extension lead, one from a spur and one from a PCB on a boiler, luckily they were not too bad but I know people who have been messed up through electric shocks. I always use my multimeter now and do safe isolation checks, also switiching off spur and removing fuse.

 

[Backboiler]

Thanks to everyone for contributing. The upshot of this is a lesson to be learned by all. Pssst, what is the fault likely to be? A lack of earth on the boiler or a stray live wire? Don't worry I'm not going to touch it, i'm curious; I've advised the letting agent to get a sparky in quickly

 

[AWheating]

sorry AW you are confusing me, what have i said that is any different to your comment, you check the supply is on, you turn it off, you check it is off then you recheck your test lamp on a known live supply, i didnt say you open up covers with the power on

maybe its how i read your post "start with the power on, check it is on using test lamp" , i thought you ment you test the powers live using a voltage tester meaning at the terminals?

did you mean using a voltage stick?

 

[stevie]

You have to do a live test, it's the only way you can check for correct polarity.

 

[AWheating]

stevie, we are talking about safe isolation of an applaince before working on it.you would not have to do any live tests to safely isolate an applaince.
If you had a fault ie.testing the wiring then yes you may have to perform live tests.

 

[Pssst]

I wonder what sort of consumer unit this property had? Was it rewireable cartridges or ELCBs?

 

[kirkgas]

maybe its how i read your post "start with the power on, check it is on using test lamp" , i thought you ment you test the powers live using a voltage tester meaning at the terminals?

did you mean using a voltage stick?

before i touch an electrical cable or connection i was taught to test as i described using my test lamp, so i do mean at the connections i am just about to touch, if you check a spur is on then off you still dont really know that there isnt a back feed at the connection so i dont know how you can confirm it is safe unless you check the actual terminals you are about to touch

 

[arran197]

I hate electricity. I really need to learn more about the whole subject. I was stupid the other day, switched off a fuse spur to rewire a boiler terminal. I must have turned it back on for some reason, I usually remove the fuse too. unscrewed all the connections fine, pulled them out the boiler and wow, bit of a shock. Lol!

 

[gasmarc]

your not on your own we all make mistakes. I have learned not to believe everything people say especially when it could be my life at stake.