2.24kW Pedestal Grinder - protection

[ekuegler]

Wondering if anyone can help me out, we have a 2.24kW pedestal grinder supplied at 440/60/3 - 0.85p.f - would using a 2.5mm2 SWA cable to supply be adequete with a 10A MCB protecting the cable.

calculated the 3 phase current to be 3.5A - anyone suggest/comment on the cable/MCB used. Are these acceptable???

 

[7anoter4]

I don't know what kind of MCB it is provided but usually it will trip for 3*Irated in 10 sec that means if the induction
motor rated current is 3.5 A at start [or at locked rotor situation] the MCB will not trip in less than 10 sec.
From BS 5467 the continuous load current for 3*2.5 sqr.mm SWA[copper conductor] -ampacity will be 31 A [cable supported by clips at 30 dgr.C ambiant.
This is more than LRC[Locked Rotor Current] let's say 3.5*7=24.5 A
The Voltage drop at start=16 MV/A/m *25 A will be 15% for not more than 150 m cable.
See:

http://www.cse-distributors.co.uk/cable/steel_wired_armoured_swa_cable.htm

 

[ekuegler]

ABB MCB is type S203MC10, 3 pole, 10A, 10KA, C Curve. In essence the set up I.e , ABB 10A MCB, 2.5mm2 3core SWA to supply a grinder rated at 440/3/60 2.24kW is adequate......?

 

[7anoter4]

If the cable length is not more than 150 m this cable is adequate.
The MCB is adequate anyway.

 

[ekuegler]

One other question, would this set up still be adequate for use on an IT or floating earth system, given the fact the system can still run with 1 such fault!