In-Rush Issue ?

[malcolmsanford]

I don't think you have a fault or an overload issue, you say in the OP that you have thermal overload relay if it was an overload issue then that would pop.

Also if it was overload the 16amp would pop first. Unless as was suggested you have a myriad of other things coming off that 40amp MCB that when the router starts up takes it over the top......then you have some issue with the 40amp breaker

It may very well be a dodgy breaker, it as been known that new accesories fail.

Try fitting the fuse, honestly my post about it was a little tongue in cheek, but I stand by that unless there is a reason not to I would always design a distribution circuit with a fuse

 

[Delectrician]

I don't think you have a fault or an overload issue, you say in the OP that you have thermal overload relay if it was an overload issue then that would pop.

Also if it was overload the 16amp would pop first. Unless as was suggested you have a myriad of other things coming off that 40amp MCB that when the router starts up takes it over the top......then you have some issue with the 40amp breaker

It may very well be a dodgy breaker, it as been known that new accesories fail.

Try fitting the fuse, honestly my post about it was a little tongue in cheek, but I stand by that unless there is a reason not to I would always design a distribution circuit with a fuse

It was miss-information on behalf of the lad i'm doing the job for.. when he contacted me he said it was the breaker in the main DB that was tripping.. when i went up today i found out it was actually the local sub-board 16A MCB that was tripping because of the in-rush current .. I had a spare 32A Type C so i put that on and it fired up fine.. I'm either going to order a 16A type D or a 20A type C .. the Thermal overload is set to 16A so i'm quite happy to go up to 20 on the MCB as i'm dubious about the type D doing the job.. what do you think?

 

[davesparks]

What is the EFLI? This will determine what mcb may or may not be fitted with the existing cables.

Earlier in post you said it was supplied with a 32A commando plug fitted and instructions to fit a 32A socket etc and set overloads to 16A, to my mind this suggests they are expecting you to fit a 32A supply.

 

[Darkwood]

Did you check the motor plate for the FLC ... I'm still scratching my head here about a 3ph 3kw motor will a FLC of 16amp?

Motor Current Charts

Check the 3ph (2nd chart) - you're looking at approx 6.5flc for a 3kw, if it runs at 6 then that sounds about right, the 16amp I would suggest is the mcb rating although incorrectly specified as it should be a 20amp B or C on a standard 3kw 3ph induction motor with a normal starting duty.

If this motor had an FLC of 16amps then it would be in excess of 7.5kw rating - so be careful when choosing the correct motor overload device, you have already been given the wrong info once.