Recent content by Loyal1

Yes I am electrician, and I thought I could consult other electricians on this forum to seek advice. But apparently this is not what this forum is about.

Agreed, but please explain to me what this forum is all about, and what is the goal of all you guys here?

Let me put it this way, what is the general practice to size the MCCB for the motors?

What is the regulation in BS 7671 to size the MCCB for a motor? Is it 1.5 times the motor full load amperes?

That is what I want to know that what will the electrician do in this situation?

No, actually I am talking about MCCB. If I have a MCCB with a frame size of 100A and a trip of 32A, then shall I have to use the Zs values for 100A or 32A?

Thanks for help ... If I have a circuit breaker with a frame size of 100A and a trip of 32A, then shall I have to use the Zs values for 100A or 32A?

The cable resistance values (R1+R2) are readily available for smaller cables. However for cables larger than 25mm2, we have to consider the cable inductance as well. Does anybody know a table which shows the reactance of cables larger than 25mm2?

Thanks all for good information. I have one basic question. What is the purpose of measuring earth fault loop impedance? It makes sense to measure earth fault loop impedance if the protective device is earth leakage breaker or RCD; but why measure the earth fault loop impedance for regular...

I will update my location, it was by mistake... Table 41.3 of BS 7671 provides Zs for upto 125A breakers only. I need the loop impedences for larger breakers (150A, 200A, 300A, etc). Where can I find Zs for the larger breakers?

Can anyone please explain what is the maximum earth fault loop impedance permitted for moulded case circuit breaker (MCCB)? Also, BS 7671 says a disconnection time of 5 sec is allowed for breakers in distribution circuits. What is the difference between a distribution circuit and final circuit?