Log in to the online community

Want to post a reply? You'll need to log in
Unusual MCB
Sparkymania 11001210537
Joined 25/03/2019 - 86 Posts
Question
Here's an interesting one.
Federal Electric 20A MCB. Had no type on it and was taking a long time to trip. Opened one up and discovered why it didn't have a type.
Others with it were ECC but virtually the same design. Only thermal. Both are plug in types called stab-lok and are bakerlite.

No instantaneous trip mechanism. Only a thermal one.



10 Replies
Sparkymania 11001210537
Joined 25/03/2019 - 86 Posts
Looking at the others on ebay I thought the colour may have some significance too as they have a label on the front stating the type so I would say they do have a magnetic mechanism.
However, some of the black toggled ones also have a type stated on the front as well so I would say the coloured ones are all later ones and they started making them with magnetic mechanisms first with the black toggles before colouring them.

I still couldn't find an RCBO with a type stated on the front or on the sides (from the ones with side pics) so that still begs the question as to whether these RCBOs have a magnetic mechanism.
 
Johno12345 11001196760
Joined 18/03/2017 - 50 Posts
the colour of the toggle has some significance, I think I have an orange one that I could open up to have a look in. 

not an RCBO, they are a bit too expensive to break
Sparkymania 11001210537
Joined 25/03/2019 - 86 Posts
Wow!
I'd never have believed it.
Shame we can't see the inside. If that were cheaper I'd get it just to open it up to check if this version has a magnetic mechanism.
It's hard to believe they would produce an RCBO with only a thermal mechanism for the overcurrent.
Johno12345 11001196760
Joined 18/03/2017 - 50 Posts
Sparkymania:
RCBOs?

I can't imagine these come as RCBO versions when they don't even have a magnetic trip mechanism.



They do

https://www.ebay.co.uk/itm/Federal-Electric-FE-Stab-Lok-30A-30mA-RCBO-RCD-Single-1-Pole-/272560115341

 

Sparkymania 11001210537
Joined 25/03/2019 - 86 Posts
RCBOs?

I can't imagine these come as RCBO versions when they don't even have a magnetic trip mechanism.
Johno12345 11001196760
Joined 18/03/2017 - 50 Posts
the breakers in the UK are Federal Electric, the USA ones are Federal Pacific Electric (fire-prone equipment) 

the look the same outwardly, but the UK ones are, apparently, ok, combustion wise. 

the RCBOs for those boards, have a little neon that lights if it trips
MHRestorations 11001209997
Joined 03/03/2019 - 250 Posts
Banned in the USA now because they caused so many fires!   The USA typically has lower fault currents than UK commercial stuff... (I blew a few fuses over there without even realizing it!)

But the thermal element can sometimes fail too, or the contacts weld... especially if closed on a fault.

Nasty things
mapj1 80733779
Joined 22/07/2004 - 1901 Posts
Hmm, Makes you wonder what else was put in at the same time.
Sparkymania 11001210537
Joined 25/03/2019 - 86 Posts
mapj1:
Common on US made equipment like UPS and so on. looking at the arc trap, or lack of it, that may not have much of a rating for maximum breaking PSSC either - or it may be a 110V part and not really intended for mains.

Was on a 3Ph DB. Due to the issue with the time it was taking to trip it was investigated and found to have no magnetic trip mechanism so the DB was changed. It was me who opened this one up to investigate.

mapj1 80733779
Joined 22/07/2004 - 1901 Posts
Common on US made equipment like UPS and so on. looking at the arc trap, or lack of it, that may not have much of a rating for maximum breaking PSSC either - or it may be a 110V part and not really intended for mains.

Log in

Want to post a reply? You'll need to log in