Breaker advice with nail gun tripping breaker
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gordo1152
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Breaker advice with nail gun tripping breaker

by gordo1152 » Sun Nov 07, 2021 12:24 pm

In my garage I have seperate breaker for the 4 sockets in there, on a breaker B16. I have bought a Nail Gun that trips the breaker on every use.

What would be the easiest way round this ( without selling the nail gun lolol)

The wiring looks to be the same rating as the sockets the house is on. could a higher rated breaker just be inserted or would it mean rewiring the 4 sockets as well .

any advice appreciated

Mr White
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Re: Breaker advice with nail gun tripping breaker

by Mr White » Sun Nov 07, 2021 9:26 pm

More information is required.
Make / model of nail gun
Size of cable to garage
Length of cable run to garage
How sockets are wired
Size of cable to sockets

An MCB is designed to protect the cable, not what you connect to it. So if you were to "insert a bigger breaker" it may be that the cables are not big enough to cope and you end up causing a fire.
This nail gun, is it brand new?

gordo1152
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Re: Breaker advice with nail gun tripping breaker

by gordo1152 » Mon Nov 08, 2021 9:09 am

yep nail gun brand new, going to check wiring today, there is a very small run to 4 sockets approx 12-15 feet at most

thanks

ericmark
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Re: Breaker advice with nail gun tripping breaker

by ericmark » Mon Nov 08, 2021 11:39 am

I would guess problem is inrush, you may get away with a C16 instead of B16 MCB, but the real point is the nail gun is poor design.

The letters on the MCB are what the magnetic part of the MCB will trip at, B = between 3 and 5 times thermal trip rating, C = 5 to 10 and D 10 to 20.

So for the B16 to trip it is drawing over 48 amp at start up, that is a lot of power.

The magnetic part of the MCB will work in about 0.01 seconds, where the thermal bit can take 1/2 hour depending on how much over load, but to ensure with a short circuit the magnetic part will work we need to measure the loop impedance so a B16 needs 2.73 ohm to trip, and a C16 needs 1.37 ohm, so before it is changed you have to measure the loop impedance, the problem is the tool to measure it with costs over £150 so not really a DIY job.

I would say take the nail gun back as faulty.

gordo1152
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Re: Breaker advice with nail gun tripping breaker

by gordo1152 » Tue Nov 09, 2021 2:59 pm

Nail Gun worked fine on the socket on the cooker box. no problem

the cable used in the garage is: basec 300/500v h 6242y/2.5

ericmark
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Re: Breaker advice with nail gun tripping breaker

by ericmark » Tue Nov 09, 2021 11:26 pm

A cooker normally has a 32 amp supply, with a B32 MCB so likely will take the inrush, but this does not make it right, if it trips a B16 then likely not designed for use from a 16 amp supply.

We see this a lot with welding sets, designed for 32 amp supply, and on a ring final they will work, but with a radial they trip the MCB.

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