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It is perfactly acceptable to install EPR cables on either cable trays or cable ladder racks. MV EPR cables are generally installed on racks rather then trays as racks provide a more sturdy installation. The biggest benefit of EPR vs say PVC or XLPE cables is that EPR cables are more flexible...

Industry practice in Europe is to provide 1800 mm ( 1200mm min) clear access all round

The beacons were bench tested at 190-135V which is their design limits with no fuse blown faults found. The fuse is used to provide internal short circuit protection. The fuse size is considered acceptable. The irony is that the design is some 5 yrs old with thousands of units sold ( so says the...

All, Thank you for the feed back. Perhaps I should clarify some misunderstanding. The beacons (with a xenon strobe tube) are "switched" through the PA system when an annuncement over the PA is to be made( they are installed in areas with some noise so the beacons high lights attention) so as...

The UPS o/p is a good sine wave with distortion (THD) of about 3% nominal. The input transf appears to be adequately rated at 75VA. The beacon is self flashing ( via internal fixed timing cct)and needs 110Vac power at all tims.

Thank you VE1BLL. The supplier did bench test the failed units at a higher voltage after repairing the failed units. I should have stated that the failure was due to a blown fuse in every case. The supplier also tested new units at a higher voltage and no faults were found.

I am on a project where we are commisioning new installed equipment. The plant UPS system feeds several 110Vac “Beacons” ( stroboscopic lights used by the PA system) . The unit ratg is about 50VA. We are finding that these beacons are failing after a few days in service. The supplier of the...

There is no requirement ( as far as standards are concerned) to insulate the said small sections of copperwork within the cable box. However many engs specify such requirement as described by arcflesh99.A good practice as it does enhance safety.

The question appears to relate to adding of stress kits to cable terminations. If so then it is standard universal practice to fit stress relieving kits ( hot or cold shrink) within the switchgear cable box to ensure that the small section of the cable which has had its armour stripped does not...

In the petrochem industry we tend to specify 300mm min.

rbulsara, The FWP is on a new build FPSO . Actually there are two units with the larger unit rated at 1300KW DOL at 6.6 KV

Many thanks.

We are requred to provide a 6.6kV DOL vacuum contactor feeder to a 500kW motor forming part of a Fire water pump package. I understand that the NEC or some other standards require that the contactor design must be of a mechanically latched type vs the conventional magnetically held type. I can...

Are you sure you are correct in your findings as it is most unlikely that the switchgear supplier can get the fuse size incorrect. You could also present/ send your findings to the supplier for his comments and if you are correct then he should be grateful.

I am assuming that the transformer is only connected (feeding) the motor and also that the transformer is adequately sized (in kVA) to successfully start the motor. If that is the case then the current arrangement (ie 200amp fuse) on the primary is fine as the fuse is only providing sc...

You can delay the Ins of the upstream CB as long as the delay meets following criteria. The upstream swgr/CB are designed to withstand the max sc current for a time ( usually 1-3 secs) in excess of your desired delay. The feeder cable is also able to withstand the sc current for the desired...

There is no technical reason for not doing what you are doing.Lugs in are generally tinned anyway and earth bars are usually untinned. As long as the connections are dry, copper oxide should not form.

In the worse case it appears that you may have to upgrade your station batt arrangement ie bigger Ah capacity. I would suggest not to rush into changing the present arrangement. With the new CB wired up, carry out checks with various cycles/O-C-O etc and evaluate the result. You will then be...

Thank you gentleman. The RTD cable is infact screened and armoured. The main motor cable is armoured as well. Because of this armouring, the cables need not be aforded with additional mech protection unless one does so out of choice. Talking to other engs it appears that there must be some sort...

We have an application of a 6.6kV feeder to a motor on a offshore platform. The motor is located in (div 2) Zone 2 area. The main motor cable is a 3c laid in ladder rack. Along side this cable we have a cable ( 7c screened) also going to the motor RTDs. The cables are not touching and have an...