BG MCB failures?

[Piratepete]

Hi Guys
Does anyone know anything about nuisance tripping of 40 Amp BG MCBs

I've been using a lot of BG CUs recently, because a) I like the design and b)They're at a very good price from 'ssh you Know who'.

However I put a 40 Amp supply in for the pump etc in a ground source heating system. The company's sparky tells me that they've stopped using BG because of repeated MCB failures.

Anyone else?

Pete

 

[polo1]

I've fitted about 15 BG boards in approx the last 6 months and had no problems (though from memory that'll only be maybe 8, 40 amp mcbs). Have you searched t'web for any info?

 

[urbanmonkey]

Only problems I've had with BG boards is the screws are not cut very well in the threads on the Neutral and Earth bars, have to wind them all the way in and out before you even think about fitting it

 

[Darkwood]

Its a pump, it has an inrush current - you mcb is possibly not suited on its tripping curve for the motor.

Find the peak inrush of the motor from either the manufacturer or a suitable clampmeter that can sample at high speed to catch the peak inrush, then consult the manufacturers of the mcb and see what the trip curve is on the mcb you have concerns with, what type (B,C, or D) is your mcb?

 

[Piratepete]

Its a pump, it has an inrush current - you mcb is possibly not suited on its tripping curve for the motor.

Find the peak inrush of the motor from either the manufacturer or a suitable clampmeter that can sample at high speed to catch the peak inrush, then consult the manufacturers of the mcb and see what the trip curve is on the mcb you have concerns with, what type (B,C, or D) is your mcb?

I fitted a C type, but in fact they have soft start now, so it wasn't required.
However it's not me reporting failures. It's the Heating Company sparks.
Pete

 

[Darkwood]

I find it hard to believe its the failure of the mcb's .... its more likely the company has not done their calculations correctly or understood their products operation, often you get a middle company importing motors and been the middle man in promoting them and selling them either as a company product or just a distributer. This often leads to incorrect product info' mis-interpreted tech spec etc... just had it myself with a large lathe made in China but sold under a british company product name, the info for me was all wrong and I challanged it saving my customer £1000 in install upgrades...

Even though you have a soft start you still have a inrush and it seems the mcb is seeing this and doing its job it was designed within its parameters... do you honestly think a product that is routinely tested in manufacturing all fail when used with this pump product, more likely they have spec'd the Electrical requirements wrong, even a 3ph soft start can still have an inrush of 5X FLC and require careful fusing selection.

Just because they fob off the mcb brand and they are a big company doesn't mean they know what they are talking about, trust me I see it all the time.

 

[Piratepete]

I find it hard to believe its the failure of the mcb's .... its more likely the company has not done their calculations correctly or understood their products operation, often you get a middle company importing motors and been the middle man in promoting them and selling them either as a company product or just a distributer. This often leads to incorrect product info' mis-interpreted tech spec etc... just had it myself with a large lathe made in China but sold under a british company product name, the info for me was all wrong and I challanged it saving my customer £1000 in install upgrades...

Even though you have a soft start you still have a inrush and it seems the mcb is seeing this and doing its job it was designed within its parameters... do you honestly think a product that is routinely tested in manufacturing all fail when used with this pump product, more likely they have spec'd the Electrical requirements wrong, even a 3ph soft start can still have an inrush of 5X FLC and require careful fusing selection.

Just because they fob off the mcb brand and they are a big company doesn't mean they know what they are talking about, trust me I see it all the time.

Ok, point taken. Really just asking. A search on Google produced a couple of disgruntled sparkies, but nothing recent to shout about.

 

[Darkwood]

Ok, point taken. Really just asking. A search on Google produced a couple of disgruntled sparkies, but nothing recent to shout about.

Not saying your wrong by the way but just take things with a pinch of salt when a company tells you something to save them costs and probably puts them back onto you.