UK Electric nail gun tripping

[brodders97]

Hi all,

First post here so go steady.

Recently installed a small radial circuit in my garage with 2.5, took it from a B16 breaker run through 20mm conduit on a wall. Tested everything with my megger with everything testing ok, happy days.

Couple of days later fired up my nail gun, on the 4th nail (roughly), it trips the 16A MCB. I know the nail gun will have a quick inrush of current as its a quick firing, so do you think changing it from a B type to a C type is a good option?

Perhaps upgrading it to a C20? Any advice would be appreciated

Cheers

 

[westward10]

I would try a Type C. I assume the circuit has additional rcd protection so fault protection is also provided if necessary, do you know the Zs at the socket outlet.

 

[Wilko]

Hi - if you’ve the patience for an experiment - I’d try using it via a long extension lead. The lead will add some series resistance which may reduce the initial current surge enough to stop the mcb tripping.

 

[telectrix]

if the Ze is nice and low, achieving an acceptable Zs for a 16A type C should be a doddle (about 1.44 ohms before correction/s).

 

[brodders97]

Hi guys, thanks for the replies.

Zs at the socket is 1.11 Ohms so nice and low, I'll go ahead and try a C type. Thanks

 

[telectrix]

what's Ze.?

 

[brodders97]

what's Ze.?

Ze measured from the sub CU is 0.91

 

[telectrix]

you're just in with the Zs if you allow for temperature correction. x0. 8, if your cable ever gets up to 70deg. which is as likely as me refusing a beer.

 

[westward10]

What's your earthing system.

 

[brodders97]

What's your earthing system.

It’s a tncs system

 

[timhoward]

Just musing, might you want to run more things at same time in future, possibly a heater in winter or extractor/vacuum?
Given conduit is already there by the sound of it I wondered if putting in 4mm singles on a B32 might be another idea to take the pressure off a bit (though from memory Zs would be right on the limit at 80%.)

 

[brodders97]

Just musing, might you want to run more things at same time in future, possibly a heater in winter or extractor/vacuum?
Given conduit is already there by the sound of it I wondered if putting in 4mm singles on a B32 might be another idea to take the pressure off a bit (though from memory Zs would be right on the limit at 80%.)

Yeah I did think of this and suggested this to him, but he assured me he only uses small power tools in there very rarely. The most being a little palm sander and what not. Most of the time a radio at most. Thought 4mm may be a bit overkill but hindsight and all that