RCD selection

[Minde85]

Hello,

I'm planing to use 3P 32A MCB for 22kW charging station (3-phase unit), but I want to use RCD also. The question is how to select right RCD?

Should I use 4P 40A RCD (22.000W/3 and then devided from 230V = 31A)

or

Should I use 4P 63A RCD (22.000W/400V = 55A)?

It's a shame, but I dont't know right selection method...

 

[telectrix]

22 kW 3 phase is approx 30A per phase. so a 40A device wouls suit.

 

[Minde85]

22 kW 3 phase is approx 30A per phase. so a 40A device wouls suit.

Thank You!

So rated current calculation for circuit breakers and residual current devices is the same?

Just want to verify it so I would know it for the future.

 

[Risteard]

Thank You!

So rated current calculation for circuit breakers and residual current devices is the same?

Just want to verify it so I would know it for the future.

22kW at unity power factor is 22,000 divided by (400 * (root 3)) which is 22,000 divided by 692.82 which gives around 31.75A per phase. I used a 4 pole 40A for this purpose last month. Plenty of headroom with it.

 

[Minde85]

22kW at unity power factor is 22,000 divided by (400 * (root 3)) which is 22,000 divided by 692.82 which gives around 31.75A per phase. I used a 4 pole 40A for this purpose last month. Plenty of headroom with it.

Thanks!