Ramp testing an MCB

[GBDamo]

Is there an over the counter device for this?

Is it something that is done outside of a lab?

Been asked a few times, how do you know it'll trip.

Or when forced to use second hand MCBs it would be nice to check them.

 

[MJPD29]

I've never heard of such a tester but I'd be interested to know others response.

 

[buzzlightyear]

Ramp testing an MCB, yes you can get one ,but you need to get for one china ,lol.
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Been asked a few times

by who the fairys wispering in your ear at night .

 

[littlespark]

No product that I know of.

Lots of boiling kettles and a clamp meter?

I think if it says 32A then it’s pretty well definite it will trip at 32. Batch tested at the factory.

 

[GBDamo]

Ramp testing an MCB, yes you can get one ,but you need to get for one china ,lol.
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by who the fairys wispering in your ear at night .

Hey, the only thing fairies whisper in my ears is how good Buzz --- is.

 

[Julie.]

Yes, it's standard with protection equipment for the higher voltages or for very large or important lv installations (eg Southampton air traffic control centre - some years ago now!).

Although ramp testing is not the thing to do.

You usually test straight forward overcurrent equipment at 2x, 5x and 10x, in addition if it has instantaneous trip (which mcbs do) 1.2x that value. (and adjust the 10x down if needs be)

Basically you prove the characteristic trip curve.

If you are testing protection relays, these have a rating of 1 or 5A, so 30x could be 30 or 150A

The standard unit I use is a sverker - which is 100A (and includes timer etc)

Alternative is a pte from smc

For higher currents or primary injection testing, I use a CSU - which is good for 600A

If you need more than this an ingvar does around 2000A

The most common ones do tend to be megger, but smc, abb, cee and many others make kit that can do it.

 

[GBDamo]

Yes, it's standard with protection equipment for the higher voltages or for very large or important lv installations (eg Southampton air traffic control centre - some years ago now!).

Although ramp testing is not the thing to do.

You usually test straight forward overcurrent equipment at 2x, 5x and 10x, in addition if it has instantaneous trip (which mcbs do) 1.2x that value. (and adjust the 10x down if needs be)

Basically you prove the characteristic trip curve.

If you are testing protection relays, these have a rating of 1 or 5A, so 30x could be 30 or 150A

The standard unit I use is a sverker - which is 100A (and includes timer etc)

Alternative is a pte from smc

For higher currents or primary injection testing, I use a CSU - which is good for 600A

If you need more than this an ingvar does around 2000A

The most common ones do tend to be megger, but smc, abb, cee and many others make kit that can do it.

How much would a device cost to 6-63A MCBs?

 

[Julie.]

How much would a device cost to 6-63A MCBs?

Not sure - I think a programma sverker 650 which will do 100A is £6k, and the sverker 750 or 780 is around £11k - it's good to 250A on it's own (add a CSU and it's up to 6000A)

But it's around £200 or so a week to hire

The pte is around the same price, but would be simpler than the 750/780

 

[Marvo]

A Megger PCITS portable primary injection tester is ZAR188559.00 and the lead set that goes with it is another ZAR18440.00 on my 2016 pricelist. This translates as about 10700.00 UK Pounds for the tester and leads at todays exchange rate. Also bear in mind that price excludes VAT and is also 3 years out of date.

If you charge 50 pence per test like the PAT testers seem to you'd need to test a hell of a lot of circuit breakers to get you capital outlay back.

 

[Julie.]

Tbh I have never understood the testing of rcds, these are generally additional protection, yet seam to be the ones fussed about "must be tested" "how do you know it works" etc

Whilst the actual main protection (mcbs these days) aren't tested at all - there isn't even a test button!

Personally, I think it should be the main mcbs protection that should be the focus on testing - if it was, the test kit would become available at reasonable prices

The stuff I mention does far more than is needed for mcbs, but as it's focused on protection equipment, it tends to be feature-rich to cover all the various types used rather than just simple overcurrent
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Ok, just checked, a sverker 650 is around £5200, a sverker 750 is £6525, and a pte100 is £5000

So I was a little out - the 750 or the pte on their own would do 250A so would cover most of the range needed

 

[M-Ty]

No product that I know of.

Lots of boiling kettles and a clamp meter?

I think if it says 32A then it’s pretty well definite it will trip at 32. Batch tested at the factory.

It's nearly panto. season, so: Oh no it isn't!

 

[Wilko]

A while back I made the WilkoSverk1000 that sort of does this... Well it was cheap anyway. The main ingredient is a transformer from an old microwave. Kept the transformer 230V primary, removed the HV secondary and replaced it with a turn or two of 10mm and got up to a couple of hundred Amps at a couple of Volts (from memory). Load current is tuned with the pliers, ha. I’d like a Variac from Santa to give it that pro look, but I understand he’s busy .

 

[GBDamo]

Not sure - I think a programma sverker 650 which will do 100A is £6k, and the sverker 750 or 780 is around £11k - it's good to 250A on it's own (add a CSU and it's up to 6000A)

But it's around £200 or so a week to hire

The pte is around the same price, but would be simpler than the 750/780

Righto, i'll have wait till next weeks overtime comes in then.

 

[Pete999]

A while back I made the WilkoSverk1000 that sort of does this... Well it was cheap anyway. The main ingredient is a transformer from an old microwave. Kept the transformer 230V primary, removed the HV secondary and replaced it with a turn or two of 10mm and got up to a couple of hundred Amps at a couple of Volts (from memory). Load current is tuned with the pliers, ha. I’d like a Variac from Santa to give it that pro look, but I understand he’s busy .

View attachment 54724

Nice safe joints you have made there Mate,

 

[GBDamo]

A while back I made the WilkoSverk1000 that sort of does this... Well it was cheap anyway. The main ingredient is a transformer from an old microwave. Kept the transformer 230V primary, removed the HV secondary and replaced it with a turn or two of 10mm and got up to a couple of hundred Amps at a couple of Volts (from memory). Load current is tuned with the pliers, ha. I’d like a Variac from Santa to give it that pro look, but I understand he’s busy .

View attachment 54724

Now that's closer my budget, do you do one in blue?

Did get any reliable results from it.
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A while back I made the WilkoSverk1000 that sort of does this... Well it was cheap anyway. The main ingredient is a transformer from an old microwave. Kept the transformer 230V primary, removed the HV secondary and replaced it with a turn or two of 10mm and got up to a couple of hundred Amps at a couple of Volts (from memory). Load current is tuned with the pliers, ha. I’d like a Variac from Santa to give it that pro look, but I understand he’s busy .

View attachment 54724

Also remeber skipping about 40 Variacs in the late 90s when clearing a pilot plant at UMIST.

I used to know a few lab ware/chemical plant Arthur Daley types who also had loads of this type of stuff, probably all dead now.
:-(

 

[Julie.]

Righto, i'll have wait till next weeks overtime comes in then.

Yeah, a tad pricy!

Shopping around you can get something to do up to 750A for the £5k mark - my initial prices were a bit off.

I had complete access to the programma range and regularly used the top end test kit - I worked for a protective relay manufacturer and consultancy, it was a bit of a shock when I left and needed to buy or hire the kit myself.

I am now more selective when I hire kit!

If the mcbs were mandated to be tested, then simpler test units at reasonable prices would become available, as it is, it's a small specialist market!

 

[Wilko]

Now that's closer my budget, do you do one in blue?
Did get any reliable results from it?

For an extra £99.99 I’ll paint it any colour .
I did have fun with it, that part was reliable. At the time I had a few MCBs that had been replaced as they seemed to be soft and I wanted to see if I could confirm it. I could load to their rated values and let them run. The MCBs were for the recycle anyway, so it was just for fun.

 

[buzzlightyear]

Wilco ,me wifey not happy having just stripped the micro wave before xmas she said what am i ging to cook the brussel sprouts now in , me said a pan ,lol..

 

[R-fur]

I got a job a few years ago to go offshore to an oil platform to do a week of nights testing 16A mcbs for the trace heating systems, did a couple of hundred of them, good money but very boring.
I have my own sverker but it is used mainly for HV protection relays.

 

[Simon47]

Funnily enough, it's something that's gone through my mind over the years. My late father had a good old fashioned stick welder with a big knob on the front that winds part of the transformer core in/out to adjust the current. I reckoned that would probably make basis of a test set Maybe with a step-down auto-transformer in front of it.
I'm thinking you need to be able to do 1x to check for false tripping, 2x to check for thermal trip, and 5x or 10x to check the magnetic trip. I had in mind a contactor to bypass the current round the under-test MCB while setting tbe current, then release the contactor and see how long it takes to trip. Wouldn't be precision timing, just "yeah it trips" sort of manual observation.