ICCB vs MCCB vs BPS

[jim dungar]

You need the real data, I have nto dealt with Excel but I have with many other utilities and it is usually just a matter of contacting the right person. Many have an engineer assigned to provising this data to engineering firms doing arc flash studies.

Xcel Energy, provides one set of fault current values for determining the AIC of protective devices and the SCCR of equipment.

They provide a different set of values for use in arc flash calculations. They also recommend that you perform arc flash calculations using at least one size larger and one size smaller transformer and then base your PPE on the worst case scenario.

This is not a case of contacting the right person. Xcel only provides realistic values to 'secondary service' customers that are extremely large. I would guess I get 480V fault values for about 10% of my Xcel customers.

 

[zog]

Xcel Energy, provides one set of fault current values for determining the AIC of protective devices and the SCCR of equipment.

They provide a different set of values for use in arc flash calculations. They also recommend that you perform arc flash calculations using at least one size larger and one size smaller transformer and then base your PPE on the worst case scenario.

This is not a case of contacting the right person. Xcel only provides realistic values to 'secondary service' customers that are extremely large. I would guess I get 480V fault values for about 10% of my Xcel customers.

Makes sense, I am only usually dealing with those large users.

 

[jim dungar]

The key phrase is 'secondary service', I can get fault values for almost every service above 480V.

 

[zog]

The key phrase is 'secondary service', I can get fault values for almost every service above 480V.

Guess I never deal with any secondary services, but it seems that excel has the right idea, but I wonder what happens with that data? Is the worst case calculated for each senario, as it should be or is the higher nu,ber just being used. I see some pretty weak studies out there being done by people that have no business doing them.