ELCB Voltage operated replacememnt ??

[ianphilip007]

hello

have a query re the above, as i came accros one for the first time yesterday. i am aware that these devices are now obsolete and should be replaced. Now many people advise to remove and replace with a modern RCD to current standards. if you do replace with a new RCD, basically covering the whole installation with a single 30ma RCD, how can 314.1 be met. i appreciate that the new RCD would not be making the installation any less safe electrically its just that if you actually install front end RCD protection covering all circuits then it is impossible to meet 314.1. apart from fitting a new CU are there any other options when removing these old devices?

 

[malcolmsanford]

There are testers around that can test the function on these units, the problems are 1) finding one 2) finding one in calibration, and so the recommendations is replacement.

The regs are not retroactive and therefore if you have an upfront VOELCB and replace it with a nice new 30mA RCD, then forget 314.1, because it can be argues that a split CU would also not adhere to this section

 

[ianphilip007]

i didnt know that it was classed as a like for like change malcom i thought that 314.1 would apply. if it is classed as a like for like change then 314.1 as you say doesnt apply retrospectively. thanks problem sorted.

 

[ianphilip007]

ive also heard that if you are installing a new dual RCD CU, they can be left in place and used as a isolator between main fuse and CU does anyone know if this is correct? sounds dubious to me as the main tails feeding would be surly undersized and it would be very confusing for the next spark who came along. can anyone shed some light on this ?

 

[malcolmsanford]

Yes that is done quite a bit. Just remove the main earth from the unit and wire direct into the MET

You can always change the tails if it is needed from the meter to the redundant VOELCB and then to the CU

 

[ianphilip007]

so by removing the earth from the coil it turns it into basically a dp isolating switch i assume they must be rated to switch the main fuse rating as that was there initial purpose. no issues i guess with having them in series with the RCD's in new board.

thankyou malcom you have been most helpful

 

[ackbarthestar]

I've replaced several VOELBs on TT systems and found that a couple actually worked very well. One of these actually protected me from an earth fault when handling a faulty floor standing brass lamp !
As far as complying with 314 by a direct RCD replacement is you can't, but you can reduce the possible perceived risk by placing a stair light with a switchable emergency light at the top of the stairs (I think its called sustained lighting)

 

[malcolmsanford]

nearly Ack .......... NON maintained

 

[telectrix]

i thought maintained was lit 24/7.

 

[ackbarthestar]

nearly Ack ..........maintained

Maybe I've used the old wording

It might be that that there is more than one type of maintained lighting M1 and M2?

Maintained M1 = light on continually whether in ordinary mode or emergency mode, just a change over switch using the same lamp
Maintained M2 = 2 separate lamps, one for ordinary use and the other charged when the change-over switch operates.

Apologies for the side track.....

 

[malcolmsanford]

i thought maintained was lit 24/7.

At our age Tel we do well to remember things at all .........missed out the Non part mate