Thanks Timesabroom for the information. I don't want to sound ignorant, but I have one more question. You say that there will be a V-Base on each side of the transformer that needs to be considered. But we know that there is only one impedance for the transformer. So how can we use both base...
I have to take the PE Electrical test on Friday; I’m having trouble solving problems involving per unit values. If the per unit values are not given and we are asked to solve the problem using per-unit, can we take per unit voltage and current as 1? Also, while taking the transformer voltage as...
I understand that when you say 180 VA per receptacle, it is for single receptacle. For duplex, it will be 360 VA per receptacle, which means a total of 4 receptacles per 15 A breaker. Am I right?
How many duplex receptacles can be placed on 15A 120V circuit? The code does not say anything about this.
If we allow 180 kVA for one receptacle (360 kVA for duplex), then it looks that I can put a maximum of four duplex receptacles on a 15 A circuit.
I see on the web that a heavy duty duplex receptacle is 1800 X 2 =3600 Watts total. The normal duplex receptacle is also 1800 X 2 =3600 Watts. How is heavy duty receptacle different than the normal receptacle?
I have a question about sizing the conductors for a single feeder supplying a continuous load. I understand that there are four derating factors that need to be applied when sizing a conductor. First is the ambient temperature factor (correction factor at the bottom of NEC table 310.16). Second...
I am confused that up to what size “motor feeder cable” can be protected by a motor starter. For example, a 75HP 460V motor needs Size 4 starter. This motor has a full load amperes of 96 amperes, which means that the conductor with ampacity of 96*1.25=120A (# 1 AWG) should be used.
I...
The table of full load amperes in NEC states that the current values shall be multiplied by 1.1 and 1.25 for power factors of 0.9 and 0.8 respectively. But in actual practice, we don’t multiply by these factors for the calculations of the motor feeder conductor. I understand that all real...
When sizing the breakers for motors, we can go up to 250% of the motor full load amperes (FLA). Does it mean that the cable should also be rated 250% of full load amperes?
Can someone tell me how much space is required for a breaker in the MCC? I know that the size 1 and size 2 starters require 14" X 20", but I need to know how much space would be required for 100A, 150A, and 225A breakers.
