What is the resistance of 1987 feet of wire of 9862 sq mils of cross sectional area

This was a state exam question ]]>

Hope all are having a great work day!

I found some NEMA Standard Electrical symbols for one line diagram. Are we following NEMA standard ?

if not where can I find standard Electrical symbols used for one line diagrams?

Thanks in advance :) ]]>

So for example, if a resistor is running at 5s on 75s, off the conductors ampacity should be at least 35% of motor FLA (OK, I get that part), but if the off/on time is different the conductors should 6.25% of ON time....???? Makes no sense... ]]>

After totaling all of spaces he came up with 4,000,657w @ 4,818 amps thus suggesting that a 5000amp serves would be acquitted.

My question is,

After the total connected loads have been determined using the square foot method, shouldn't you multiply the total by 1.25% therefor the service size should be 6000amp?

If it is necessary to apply the 1.25% to the total Con. load, where in the NEC would it be referenced? ]]>

Shame on me for not asking sooner, but is this sequence the same for all buildings (all other things equal)? For example, if I have a 5 story multi-family building in NY, will the matrix be the same as a 5 story multi-family building in AL? Is this determined by the local AHJ or Fire Code? Is it taken directly from NFPA 72?

Thanks... ]]>

I have a hotel that i am working on. Each guest room has a refrigerator and a coffee maker, for a total of 20 rooms. What demand factor does the NEC allow me to take on all the refrigerators and coffee makers? the only section that I could find that would fit this is section 220.56 (NEC 2008). Since I have more than 6 'units of equipment' (as per the table), I would take a 65% demand factor. But is this the right section to be using? Section 220.56 is titled "Kitchen equipment - Other than Dwelling Units".

Thanks again! ]]>

I have a voltage drop calculation question.

I have 5 LED 208V 1 PH Area lights going to be installed in a parking lot 100 ft. apart from each other, the 208V source also being 100 ft. from the first light pole.

Each LED light draws 3 Amps.

I plan on installing #6 Al USE, but not sure which end of the circuit to start the calculation.

Can someone show me the procedure and which end of the circuit to start on?

Thanks in advance ]]>

How many receptacles needed for 50,000 sq ft office building?:? ]]>

Can anyone share sample Electrical Load calculation spreadsheet with panel and feeder sizing for commercial buildings?

Thanks ]]>

I'm being told that even though the normal position of these is closed, it is required that the motors be disabled in the event of a fire (like a hold open door) such that they need to be opened manually and such that they will promptly shut again on gravity after pushing them open; as opposed to the longer process of opening them with the door paddle resulting in the door being opened for a longer period of time.

I've never heard of this. Have any of you? How do you normally handle it? ]]>

The 125A Feeder ( 3 - 1/0 THHN CU) is run underground in a 2" PVC Conduit 400'LF to a Underground Pull Box.

The 125A Feeder is tap with a 125A 240V 1 Phase Meter Main with a calculate connected load of 105 Amps and another tap with a 100A 240V 1 Phase Meter Main with a calculate connected load of 53 Amps.

Is this a legal Tap as per NEC 240.21(B)5? ]]>