Aico 3000 Range
This official sponsor may provide discounts for members

Discuss Testing CBR units in the Electrical Engineering Chat area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:  American Electrical Advice Forum

CBR units appear difficult to trip time test on some occasions. Not only myself but other colleagues too when testing 300ma/500ma CBR units find even using a variety of manufacturers instruments that multiple trys are required before a succesful trip test. Often no trip occurs at all. Is this impedence related. ie TT systems.
 
Bulk Workwear - Clothing Suppliers for the Whole Forum Network
This official sponsor may provide discounts for members

davesparks

-
Mentor
Arms
Esteemed
I'm not good with acronyms so you'll have to remind me what a CBR actually is.
I know it's one of the permutations of an RCD, my guess would be its an earth leakage relay operating a circuit breaker via a shunt or release
 
  • Thread Starter Thread Starter
  • #3
I'm not good with acronyms so you'll have to remind me what a CBR actually is.
I know it's one of the permutations of an RCD, my guess would be its an earth leakage relay operating a circuit breaker via a shunt or release
Hi Dave.

It is a moulded case circuit breaker mccb with either remote setting device or add on Vigi Unit.
Frank
 
a) Do any specific MFTs take offense.
b)( is first trip event a common fail - next one better )
..never fully trusting RCD technology has a reason for existence ...
 
  • Thread Starter Thread Starter
  • #5
a) Do any specific MFTs take offense.
b)( is first trip event a common fail - next one better )
..never fully trusting RCD technology has a reason for existence ...
:Any number of manufacturers mft units are used. Seems to be a common thing amongst electricians I have come across. Perhaps 60% or so such units act this way.
 

davesparks

-
Mentor
Arms
Esteemed
Is it vigi type units which fail or seperate earth leakage relays with core balance transformers?

Core balance transformers need to be correctly installed to work properly, including getting the conductors centred in the coil, not off to one side etc.
 
  • Thread Starter Thread Starter
  • #7
Is it vigi type units which fail or seperate earth leakage relays with core balance transformers?

Core balance transformers need to be correctly installed to work properly, including getting the conductors centred in the coil, not off to one side etc.
Seperate controls. You know the type. 3 "inch square panel small rotary knobs for time delay and Current setting. Core installation complete in all cases. This issue is just occasional but given we install dozens annually the test failure rate though small is significant. It's a mystery though an Engineer from Kewtech did suggest that rcd testers specific to CBR units were available.
 

davesparks

-
Mentor
Arms
Esteemed
Seperate controls. You know the type. 3 "inch square panel small rotary knobs for time delay and Current setting. Core installation complete in all cases. This issue is just occasional but given we install dozens annually the test failure rate though small is significant. It's a mystery though an Engineer from Kewtech did suggest that rcd testers specific to CBR units were available.
I know the type very well, I've installed a fair few in various bits of equipment.
I've never yet had an issue testing them, I usually test them at 30mA and a randomly selected higher setting.

At the moment I can't think why they would not pass testing with a normal tester.
 
  • Thread Starter Thread Starter
  • #9
I know the type very well, I've installed a fair few in various bits of equipment.
I've never yet had an issue testing them, I usually test them at 30mA and a randomly selected higher setting.

At the moment I can't think why they would not pass testing with a normal tester.
Thanks Dave.
If we ever discover the answer I will be sure to let you know.
 

Reply to Testing CBR units in the Electrical Engineering Chat area at ElectriciansForums.net

uHeat Banner - Forum Discount Available
This official sponsor may provide discounts for members
CK Tools :) The professionals choice when it comes to Electrical Tools
This official sponsor may provide discounts for members
Top Bottom