Hi all,
when specifying a motor disconnect switch according to art.(430.110) of NEC it shall not be less than 115% of the FLA of the motor; sticking with this formula will lead to a disconnect rating less than the rating of the circuit breaker protecting the motor which means the inrush...
hello all,
i am running feeders to (2) 3 phase , 480V, 75HP pumps. FLA for each pump is 96A and they are located at a distance of 176 feet from the panel.
according to code:
96A * 1.25 = 120 A, then adjusting for voltage drop gives me #1/0 wires
now do i need to add derating factor if i am...
Hello all,
I have a main circuit breaker panel that is fed from a 480v-208v transformer and the transformer is required an over current protection on the secondary, would the main circuit breaker be considered as protection for the transformer secondary or it is considered as protection only to...
Hello folks,
I am working on a project that involves (8) 3 phase, 480V, 75HP pumps fed from an existing MCC. We are replacing those pumps with new ones at the same HP ratings. The existing starters in the MCC have circuit breakers as an overcurrent protection rated at 150A. According to the NEC...
I am designing a project for a sport's field lighting. There is an existing high voltage 4160V/2400V- 208V/120V 50KVA transformer for the existing field and parking lights. After selecting my new field lighting fixtures, the load would be 3 phase, 175A only for the field lights and add about...
My understanding of an emergency panel is that it has to be connected ahead of main service switch so in case of a loss in power due to a short circuit , the emergency lights will stay on.
I am looking at some design drawings and i see that they connected emergency lights through a circuit...
I used to believe that a circuit breaker in panel can be used as a disconnecting means for motor loads like in boiler rooms when the panel is within site until i read Article 430.109 in the NEC (NFPA 70) defines the type of disconnecting means allowed for motors and controllers. I am concluding...
Hello all,
I would appreciate any input on this,
I am having talks back and forth with the electrical contractor regarding grounding a newly installed transformer in the electrical room to existing grounding system, that is what the plan calls for. His problem is that he can't locate or find...
Does anybody know if during construction (complete electrical, mechanical, structural and FA renovations) the existing FA system can be disabled for a period of time until construction and new FA system is complete? I am working on a site for the government in Florida and the construction guys...
Hello all,
I am doing a Project in NY for an Italian Pizza Restaurant, there is no Fire Alarm System in the building, but the place has a sprinkler system. According to the NY city code requirements I need to have duct smoke detectors and if there is a trouble they shall activate a visible or...
Hello all,
I am doing a Project in NY for an Italian Pizza Restaurant, there is no Fire Alarm System in the building, but the place has sprinkler system. According to the NY city code requirements I need to have duct smoke detectors and they shall activate a visible or audible signal in an...
Hello all,
we are doing some design work on a Kitchen and cafeteria in a federal building in NY that has an existing simplex 4100 fire alarm panel. I am trying to find out if it is required by code to shut down power from electrical equipment under the hoods such as oven, toaster and grill in...
Hi Guys,
I am having an electrical upgrade for a building in New York where I have a meter bank and pullout fused switches protecting each apartment panel, I was asked to provide main circuit breaker panels in each apartment for maintenance issues, is this allowed by code to have two...
I am taking the PE exam this Oct. 2010 in electrical power. I bought the sample questions and solution book from the NCEES, the problem is that it only has one sample exam (80 problems) and i heard that the material from the ppi2pass is different than the actual exam and that i might be wasting...
I am an electrical engineer 5 months away from taking the P.E. exam in the state of NY, then I have to wait another 3 months to get the result so I am looking for at least 8 months before I can start a consulting business in engineering. I am enthusiastic and ready to grab business now and am...
