Chilton 60A 770mA Current Operated ELCB

[hawk84]

Came across this recently doing an EICR.
Just wondering if anyone has any information on this.
Its a Chilton 60A Current operated ELCB
Voltage Rating 415
Current Rating 60A
Rated Tripping Current 770mA
Catalogue No. CEHB3060/C

I'm curious about the 770mA Rated Tripping Current.
There are some photos that may help.

 

[Pete999]

Difficult question Mate I have been on google trying to find ananswer and all I get is the operation of a Voltage ELCB when I try Current ELCB all I get is now known as RCDs. Maybe best to wait for Lucien to appear he would probably have the answer. Lucien is the Forms go to guy on all things out of the ordinary.

 

[Lucien Nunes]

'Ello Pete!

For practical purposes it's an RCD by another name. Historically, ELCB implied voltage-operated simply because that was what was being made when the term was introduced. When they started making 'modern' differential current-operated types, before the term 'residual current' was standard, they referred to them as current-operated ELCBs.

It's got the same bits as a modern one, just bigger. The breaker and its tripping mechanism may in fact be the same as used in some VOELCBs, just with the addition of the balance transformer and what seems to be a rather elaborate test arrangement, with an auxiliary transformer behind that board near the test button.

As for the 770mA tripping current, I can't think what that derives from. For a touch voltage of 50V that would require Zs < 65Ω, which doesn't ring any bells with me. What is it protecting? It looks like it's inside a machine panel, with those numbered cables in the Redspot fuseholders. What is the earthing system of the installation?

 

[Pete999]

'Ello Pete!

For practical purposes it's an RCD by another name. Historically, ELCB implied voltage-operated simply because that was what was being made when the term was introduced. When they started making 'modern' differential current-operated types, before the term 'residual current' was standard, they referred to them as current-operated ELCBs.

It's got the same bits as a modern one, just bigger. The breaker and its tripping mechanism may in fact be the same as used in some VOELCBs, just with the addition of the balance transformer and what seems to be a rather elaborate test arrangement, with an auxiliary transformer behind that board near the test button.

As for the 770mA tripping current, I can't think what that derives from. For a touch voltage of 50V that would require Zs < 65Ω, which doesn't ring any bells with me. What is it protecting? It looks like it's inside a machine panel, with those numbered cables in the Redspot fuseholders. What is the earthing system of the installation?

Thanks Lucien knew you would be able to come up with the goods, hope the OP appreciates your efforts.

 

[hawk84]

Hi, thanks for the quick response.
It's the front end RCD on a T.T. Installation. The installation is a water pumping station, and the RCD is mounted within the MCC panel. It just seemed odd to me the 770mA rating. It's as if it's given the rating after on site commission and testing, as the details are hand written. I have more tests to carry out on the site, and will probably be doing some remedial/upgrade works as this is the only RCD on the installation.