Functional testing of MCB's??

[La Poste]

It might sound a bit daft but is there any way of functionally testing MCB's?
It's easy to confirm whether an RCD is functioning correctly but is there any way of testing an MCB?
I've just been reading about counterfeit goods and how some MCB's are manufactured with absolutely no working parts inside them at all and that is what led me to asking this question.
Cheers.

 

[Risteard]

You'll know the counterfeit ones by their weight.

 

[Sparky Ninja]

I've checked out counterfeit MCB's before and I could tell also by the resistance and action of closing the MCB.

 

[La Poste]

I've checked out counterfeit MCB's before and I could tell also by the resistance and action of closing the MCB.

The resistance?
Could you be more specific?

 

[Sintra]

The pressure taken to close the device. A fake tends to close a lot easier than a genuine mcb.

 

[malcolmsanford]

As Widdler said if you have over the years set 1000's of MCB's you know what they should feel like when you set them. There is a slight resistance to the action and a click like sound.

The counterfeit ones feel just like a rocker switch, there is no resistance it just holds in and you know there is something wrong. It's lot like a mechanic, he listens to an engine and says that don't sound right, and you look at him and think how does it not sound right, it's experience.

 

[mcb-expert]

Previously we had different arrangement which was in-house. But, we now use a Portable Tester & Demonstration Equipment for MCB from SCR ELEKTRONIKS.
We even got a fixture (mechanical jig) to just slide on the circuit breaker and the current connections are done with pneumatic that really saves our time.

 

[Engineer54]

Previously we had different arrangement which was in-house. But, we now use a Portable Tester & Demonstration Equipment for MCB from SCR ELEKTRONIKS.
We even got a fixture (mechanical jig) to just slide on the circuit breaker and the current connections are done with pneumatic that really saves our time.

But what is the cost of one of these portable MCB test sets?? You have been asked this very same question before, but haven't given any indication as to the cost of these units...

 

[Former Sponsor TM]

I bet that they cost a lot of money. MCB/protective device testers tend to fall into the remit of primary current and secondary current injection test sets.

Primary current injection test sets tend to be used by manufacturer's of protective devices protecting a supply network (11kV+). They can inject kA's of current into a system and record the time it takes for a protective device to operate.

Secondary current injection test sets can be used to inject a smaller amount of current over a period of time in order to measure the operating time of an MCB or relay, or record the amount of current and time it takes for a device to operate in a staged overload scenario.

Either way I would assume at least £5k....That said, the MCB tester that MCB-tester looks cool but I'd be interested in a price, too

 

[44ALLAN]

It might sound a bit daft but is there any way of functionally testing MCB's?
It's easy to confirm whether an RCD is functioning correctly but is there any way of testing an MCB?
I've just been reading about counterfeit goods and how some MCB's are manufactured with absolutely no working parts inside them at all and that is what led me to asking this question.
Cheers.

Or you could take a wander lead from the load side and touch...........................nahh don't go there lol

 

[amlu]

separate consumer unit, combined with an ammeter and dummy load of electric hob/heater/couple of kettles etc.

 

[PEG]

I can see the interest in testing MCB's but beyond mechanical test of switch and inspection of type,condition etc,you just have accept the given properties from a reputable manufacturer.Like we do with Airbags and Condoms.

 

[Engineer54]

I bet that they cost a lot of money. MCB/protective device testers tend to fall into the remit of primary current and secondary current injection test sets.

Primary current injection test sets tend to be used by manufacturer's of protective devices protecting a supply network (11kV+). They can inject kA's of current into a system and record the time it takes for a protective device to operate.

Secondary current injection test sets can be used to inject a smaller amount of current over a period of time in order to measure the operating time of an MCB or relay, or record the amount of current and time it takes for a device to operate in a staged overload scenario.

Either way I would assume at least £5k....That said, the MCB tester that MCB-tester looks cool but I'd be interested in a price, too

No not really, we will be testing both primary and secondary on both all our MV and LV Switchboards. Generally primary injection will test the main current paths through switchboards and breakers, while the secondary injection proves the CT's and associated meters, relay modules etc... We use the megger PS 3000 for our primary injection needs, Not too sure this time round, on what is going to be used for our secondary injection equipment...


I'm with you on the cost of this portable MCB testers.... Not too much different from a MCCB test kit, in operation, except for the current output, and therefore probably cost!! lol!!

 

[mcb-expert]

I bet that they cost a lot of money. MCB/protective device testers tend to fall into the remit of primary current and secondary current injection test sets.

Primary current injection test sets tend to be used by manufacturer's of protective devices protecting a supply network (11kV+). They can inject kA's of current into a system and record the time it takes for a protective device to operate.

Secondary current injection test sets can be used to inject a smaller amount of current over a period of time in order to measure the operating time of an MCB or relay, or record the amount of current and time it takes for a device to operate in a staged overload scenario.

Either way I would assume at least £5k....That said, the MCB tester that MCB-tester looks cool but I'd be interested in a price, too

See I got one from my department which we procured for 1500US$, but that was for a particular qty that we purchased for test as well as demo. I don't know the unit price, but why don't u ask the manufacturer?

 

[Marvo]

For MCB's it isn't viable to test their operation unless your setting up to do thousands of them. With regard to counterfeiting most manufacturers have a webpage on how to spot counterfeits of their specific brands based on the actual counterfeit items they've encountered.

 

[Engineer54]

For MCB's it isn't viable to test their operation unless your setting up to do thousands of them. With regard to counterfeiting most manufacturers have a webpage on how to spot counterfeits of their specific brands based on the actual counterfeit items they've encountered.

Far to cheap to just replace when a MCB is suspect!! Unless your dealing with obsolete MCB's, which in the main were crap, (GE/SQ D, amongst others) when they were new anyway!! lol!! Most of those CU/DB's would be better off changing, ...and cheaper in many cases!! lol!!

 

[mcb-expert]

For MCB's it isn't viable to test their operation unless your setting up to do thousands of them. With regard to counterfeiting most manufacturers have a webpage on how to spot counterfeits of their specific brands based on the actual counterfeit items they've encountered.

I respect your opinion & I agree it may not be viable in homes (but I think electricians should do it nevertheless).

Consider this: If your MCB is protecting a high-end equipment, I think it is a good option to have the inexpensive PAT to be sure than to be sorry later Besides if you are buying from various manufacturers, or from an overseas manufacturer especially (& we know the unwritten law of the land that most aren't even manufactured by the brands themselves but by their vendors/OEMs) a tester like this comes nifty!

Apart from this we (not myself but some other department in our company) use it for demonstrating the MCBs we drop in our systems so as to ensure our brand performs like a Merlin Gerin.

I agree with you that there are other ways to check the counterfeit.

 

[Engineer54]

Most of the electricians on this site are self employed one-man bands, no-way would the expense of an MCB test kit such as you have been issued, be a viable proposition, be they house bashers, commercial or industrial. ...I would even go as far as to say that it would even be outside of most smaller outfit's/companies price range.

 

[Marvo]

I respect your opinion & I agree it may not be viable in homes (but I think electricians should do it nevertheless).

Consider this: If your MCB is protecting a high-end equipment, I think it is a good option to have the inexpensive PAT to be sure than to be sorry later

I'm going to disagree about general electricians testing MCB's. In commercial andespecially domestic installations MCB's are used to protect the cabling of the installation against thermal damage due to overload, they're not protecting the high-end equipment or the appliance itself. They're notoriously poor at protecting against marginal overloads even up to double or triple their rated tripping current and even more sometimes depending on their curve of thermal operation. When it comes to short circuit protection and magnetic operation it's a cascade arrangement where if one MCB downstream in the network fails to operate the upstream MCB will trip to the fault still giving the network being supplied equal protection.

Add to this the lack of financial viability of carrying portable current injection kit plus the safety aspects of this kind of procedure and kit, I'm firmly in the no camp at the moment.

 

[Engineer54]

I'm going to disagree about general electricians testing MCB's. In commercial andespecially domestic installations MCB's are used to protect the cabling of the installation against thermal damage due to overload, they're not protecting the high-end equipment or the appliance itself. They're notoriously poor at protecting against marginal overloads even up to double or triple their rated tripping current and even more sometimes depending on their curve of thermal operation. When it comes to short circuit protection and magnetic operation it's a cascade arrangement where if one MCB downstream in the network fails to operate the upstream MCB will trip to the fault still giving the network being supplied equal protection.

Add to this the lack of financial viability of carrying portable current injection kit plus the safety aspects of this kind of procedure and kit, I'm firmly in the no camp at the moment.

I quite agree with you Marvo, i should have mentioned something along these lines, instead of concentrating on the financial burden side of things. Any high end equipment, ...any equipment come to that, if it needs/requires close thermal/magnetic protection, then the manufacturer will have/should incorporate suitable protection measures.

Exactly the same as the fuses in plug-tops and FCU's are not there to protect appliances and equipment, only the cord/lead supplying them...