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Hi Can anyone pls tell me if a 45kVA 480v-208v remote transformer require a disconnecting means? Thanks

I wonder what is the salary of an electrical engineer with three years of experience (in Dallas,TX) in lighting and power.

Thanks everyone!! Hi dpc... I am using NFPA calculation. So is it going to change the arc flash. If not, why are we doing the single line to fault calculation?

While doing the arc flash study, I wonder what effect does the single line to ground fault has on arc flash current and incident energy? When I performed the arc flash study, I did a mistake of low resistance grounding the transformer and generator instead of solidly grounding them. There was...

By UPS breakers, I mean both the breakers on the switchboard and the internal breakers. These ups has internal breakers with long time and instantaneous settings. So I wonder, what should be the inst. settings of both the breakers (internal breakers and the one on the swbd feeding ups) ? Thanks

Hi, I am currently doing a coordination study and I would like to know how to set the UPS instantaneous setting. I know I have to calculate and add the inrush current of all the pdu transformers and set the instantaneous setting of the static bypass switch circuit breaker to a level where it can...

forgot to attach the drawinghttp://files.engineering.com/getfile.aspx?folder=2c77f4a1-be8b-43da-9fcb-633f8f6b29c9&file=SWGR.jpg

Hi I am currently working on the coordination study using SKM power tool analysis. Questions regarding the ZSI settings. The SKM support told me that I have to input the Trip/Delay time(sec) for the breakers with ZSI module. The manufacturer said that the minimum trip time is 0.1. Please have...

The following glove class table comes from ASTM D120-95 00 500V 0 1000V 1 7500V 2 17000V 3 26500V 4 36000V It is always good to include this in the appendix of the arc flash report.

Is it true that the outdoor pad mounted transformer do not have a short circuit rating? Instead, manufacturers provide us with ansi damage curves..

Thank you guys for responding!!!

What is bus bracing rating?

Jghrist...Here is the one line diagram...Please have a look at the uploaded filehttp://files.engineering.com/getfile.aspx?folder=9d189a30-54ac-4b4d-815d-253710837b69&file=one_line.jpg

Thanks for responding.. jghirst- Yes the settings provide coordination with the transformer fuses. I don't have a good knowledge about the closed loop system and currently I am doing the coordination study using the SKM powertool analysis. My manager asked me to do this. So I am kind of...

There are two vista switchgears, one fed from A-side and the other one fed from B-side. These switchgears serves transformers. Since the B vista switchgear is energized through the closed loop switch in each transformer a fault on a primary conductor will be fed direct from the utility and...

sorry I gave wrong information. The current on the primary side of the transformer is approximately 42Amps

Hi, I am trying to select a S&C vista device. Downstream of this device is a fused transformer rated at 2500kVA, 34500kV/480V. The transformer fuse is rated at 8A. The current on the primary side of the transformer is only 5A. Can I select a vista fuse rated at 100A? Is it too high?

What is a inverse definite time relay? How does it work?

It is a Vacuum fault interrupter.

I have a question regarding the protective device voltage. The utility is 34.5kV and the relay connected to the S&C vista SWGR is rated at 23000V. I always thought that the protective device voltage should always be higher than the bus voltage. Please advise... Thanks