Greetings,
I have received available fault current data from the utility in the form of L-L instead of Three phase. I have not seen this before from my local utility. I am wondering if this is a mis-speak because I was given this data third hand.
I have not been successful reaching the utilty...
Greetings -
I need to select coordination settings for a Basler BE1-51 between the PG&E SEL-251 and the (5) Cutler Hammer RBA-400 125E fuses for the 5 substation feeds.
I am confused by the info from the utility. Here is what I was given:
Relay = SEL-251
CTR = 1200/5
Ground: curve = VI, T = 1...
Hello and help.
My sc report results don't make sense. I have a 3000A 480/277V building with utiltiy reporting 51k AIC. For some reason all the 208V fault currents are calcuulated in the 500A range. When I model the 208 v portion separately, the results are in the 5000A range. Any ideas whate my...
Greetings!
I am performing a short circuit and arc flash for a multi-story building with 4000A 480V busduct risers. Each floor has several plug-in breakers. Do I model this busduct as one long bus or each "floor" is it's own bus? I just need to err on the conservative side for a preliminary...
(E)400A-1P service. Office bldg being "mostly gutted". (E) and (N) lighting and rcpts to be added to 2 new panels. 2 (E)panels to remain have HVAC & misc. Do I treat this as "new" or "addition"? Any guidance is so appreciated!
I'm trying to coordinate breakers using SKM software. I don't understand how the cable damage curves come in. Aren't cables damaged in more of an long-term heating "overload" situation and not in the .1 or 1.0 second range? I actually have not considered cable damage before so I would love some...
It's been a while so I'd appreciate some help. What is the difference between and the significance of MCA (minimum current ampacity) MOCP (maximum overcurrent protection) FLA (full load amps) and LRA (locked rotor amps)?
I've got a chiller with MCA, MOCP, and RLA
and a ac unit eith FLA and...
How many amps can I put on this 750kW cat? Manufacturer uses 0.8 as power factor. My 480V building is at 0.95 power factor.
750kW/0.8 = 937kVA
750kW/0.95 = 789kVA
Building Load is 1020A.
1020 X 480V X root3 x 0.95 = 806kVA
So, one guy says use the 937kVA rating because the bldg pf is .95...
