Chiltern ELCB

[lilman]

At a property fitting some boiler control wiring and discovered that the old ELCB was suspect. Then discovered a fault on a socket - Neutral and CPC swapped. Why didn't the ELCB trip? The home owner has been using the socket for his PC, monitor and printer etc for years apparently with no problem. I seem to remember the ELCB should trip if more than 50V is present on the CPC. What's that all about then?

 

[Evans Electric]

An old ELCB like that probably doesn't work . Did you not test it ?

I should replace it anyway. Is this an overall ELCB on a TT ?

 

[OnOff]

Guessing you mean "Chilton". Seen a few round my way. They didn't measure leakage current BUT leakage VOLTAGE from memory and tripped if they saw over 50V on the earth. I have info / a link on this somewhere. The cleverer people on here will add to this. Again, from memory there is / was some issue with them so it's a change to a modern RCD job I'm thinking..........

 

[kerching]

Was it not a black thingy. Size of an REC2 with a separate Earth wire going to an external Rod? FVO...Fault Voltage Operated if I recall. Noah had one for his bilge pumps....bin it, burial by council. They used to be able to trip adjacent FVOs out on a caravan park that I had the misfortune to do some work on. (why do 'static home' owners always have loads of knackered timber under their vans?)... :coat

 

[Steve3948]

On terraced houses when they tripped, they tripped next doors also, no fun if you was watching Else Tanner on Coronation Street :innocent

 

[steptoe]

I was always of the opinion they were illegal and if you were doing any work on an install protected by a voltage trip you had to condemn it,

it either got removed or replaced with an RCD/Main Switch, whichever was appropriate.

they werent even considered adequate for isolation,

:C

could be wrong as far as BS7671 goes, it may have been an SR.

 

[speedster]

I've come across a few of these over the years.

Had a problem with one tripping years ago, and as someone else metioned,adjacent houses with voltage operated trips would also be affected. These devices are not reliable for two reasons. The Chilton devices were not the best quality. I had numerous failures of this particular make. (Crabtree also made this type of device,but theirs were better quality and more reliable).The big problem with these devices is that they can be rendered useless by parallell paths to earth.

Some will correct me,but I seem to remember these becoming obsolete in 1986 !

Personally I would strongly advise the customer to have their voltage operated device replaced for a current operated device.

I would not deem an installation 'satisfactory' if it was a TT installation with a voltage operated device as as opposed to a current operated one.

Best of luck.

Speedster.

 

[lilman]

This is on a TT install. I did replace the ELCB with a main RCD - not a brilliant solution, but safer than before.

I explained to the owner about an upgrade, but he says the wiring is fairly new and can't see that it needs any further work - as it's only 35 years old!

I wouldn't have got involved in any of this if the 'heating engineers' hadn't managed to make water dribble from the light fittings whilst filling the system!

 

[Evans Electric]

I'd forgotten those things were voltage operated , thanks Steptoe, so yes it needed to go. We were advised some while back to replace them if we came across one. IIRC

 

[davetheglitz]

The theory of the ELCB's is valid but with bonding to buried pipes it is possible to have multiple earth paths - so the full trip voltage may not be seen. If next door is TNCS and shares the metal pipes then it might never trip.

On the other hand I've come across one which tripped perfectly at x1 - just happened that the pipes were in the opposite corner of the bungalow to the earth rod. Very difficult to insist on replacing as the device is functioning perfectly to the latest regs.

If the earth is removed from them they can be used as an isolator.

 

[batty]

Not always a straight forward job replacing them with an RCD though especially as there may be N-E faults on the existing installation that could be 50 years or even older.