Doing a further dig into the NEC it looks like I am able to classify the circuits as Class 1 Remote-Control and Signaling circuit (assuming my CPT is a Class 1 transformer). I can't however find any grounding requirements that are associated with class 1 circuits. I have dug pretty deep into...
Greetings,
I have a 120Vac Control Cable that runs from a small 100VA 1-Ph CPT located in a MCC to a Relay Panel. Am I required to run a equipment grounding conductor within the cable to consider it TC-ER rated? There are numerous of these cables that are running between the two pieces of...
7anoter4,
Yes you have the same question as I do. Why does the 1hr. time limit come in for 133% insulation? Also how much current/potential is allowed on the shield for over 1 hr on a 133% insulated cable. If it is zero (Current/Voltage) then I would be forced to add some type of protection to...
Can anyone give me an explanation of how duration of line to ground fault is tied to the insulation level (100%,133%, 173%) of the cable? See notes 1,2,3 in NEC 2011/2014 Table 310.104(E). I'm curious how these times were determined and if fault current has anything to do with this duration...
Greetings,
I have a NFPA 780 question on antenna support lightning protection. Currently I have a building with a lightning protection ring and air terminals mounted 2' from the edge of the ridge line of the building with 20' horizontal spacing. Antennas and their supports were added after the...
Does anyone know in the 2011 NEC the section that requires 125VDC Panels that has a battery charger as one of the branch breakers and DC batteries connected to the main breaker, the panel to have a label listing multiple sources? Does it exist?
Any help is appreciated.
Hello Everyone,
I am trying to calculate the positive, negative, and zero sequence subtransient reactances for a generator. I asked the vendor for this information and was of course supplied with different information than I requested. Is there a way to calculate (pos,neg,zero) subtransient...
