Portable HPU Panel overload protection query

Depending upon the exact circumstances, it probably be argued that the fuse or circuit breaker protecting the fixed instalation does also protect any appliance connected thereto, therefore overload protection only may suffice.

An isolater may not be needed. An emergency stop button is probably required, but isolation for maintenance or repair could reasonably be achieved by unplugging the machine, or by locking of an isolater in the fixed installation.

I'm not sure I have the picture, having not see one before .. Are these things in effect jumbo plug in appliances, that are relying on the protection of the socket they plug into?,

or is it more complex,

also  does the thermal overload device protect the whole thing, and how does that compare say with the wiring size used.?

Does it need any kind of emergency stop, or is that handled by whatever gets fed by the hydraulic hoses.


If so it may be all right, it may not - it rather sounds like it depends what plug gets put on it, whcih is not so great, but also part of me is thinking is this equipment that is  covered by the 'machinery directive, and all that entails !

Mike

Hi and Welcome.


The motor presumably has the normal overload against overcurrent operation so will be fine. The site sockets will be red 3 phase I presume with BS4343 connectors, and these or the generator will have RCD protection against Earth faults. The units presumably have soft or star-delta starters. It all sounds pretty normal for larger equipment and is probably covered by BS7909 more than BS7671 for all the distribution and power equipment. It might be worth fitting a phase failure relay to the starter because this is the most likely thing to cause motor damage.


For those not familiar, I would expect a motor, hydraulic pump, fluid reservoir, pressure regulation valve, and hydraulic circuit connectors so not much electrical except the starter, on-off buttons, and motor starter. The stop button could be a large lock-off type as an emergency stop, but nothing too dire will happen even with a burst hose, just a mess. There is probably nothing moving that can be touched.


The only point is that the Earth connections and cables should be regularly tested for adequate continuity, depending on site usage and conditions.

Cheers all for the insight.


I had already added a phase rotation/voltage detection relay as suggested.


After managing to question one of the suppliers, they now fit local isolation and short circuit protection as standard (as I has suspected they should have been), as whatever provides the protection upstream may not be properly rated to protect the motor in a short circuit situation.


Now I just have to cram 40% more gear in the same size box!!


Cheers again,


Gary