I have project its high rise building where the electrical designer provided motor contributions estimates with shirt circuit study for 240V single phase hvac motors. All combined hvac motors of all the units makes difference. Their is also elevator motors 50hp, 30hp at 208V three phase.
The...
I have sprinkler pipe in church garage setting. The sprinkler pipe has heat trace. Does the circuit for sprinkler pipe require ground fault protection of equipment (GFPE) or not according to NEC?
@ FacEngrPE those are phase conductor sizes. We know how to size phase conductors. It says per phase. Table does Not say equipment grounding conductor sizes
@cuky2000 how does one size equipment grounding conductor between service rated fire pump controller and fire pump? I thought NEC 2014 section 250.122 says based off of upstream breaker setting. Upstream breaker in this case is in fire pump controller. So one would size the equipment...
@cuky2000 my understanding is that NFPA 20 chapter 10 covers breaker inside fire pump controller and breakers outside of fire pump controller between utility and fire pump controller are sized per NEC 695 also same information mentioned in NFPA 20 but chapter 9. So my previous question how does...
@ cuky2000 post is questioning NFPA 20 chapter 10. The breaker post #1 is talking about is inside the listed fire pump controller NOT between utility and fire pump controller. How does NEC 695 come into play?
I have dedicated utility service that feed service rated fire pump controller to fire pump 100 HP, 480V, three phase. I need to know the circuit breaker internal in the fire pump controller trip rating so I can size equipment grounding conductor between the controller and fire pump NEC 2014...
@Stevenal (Electrical) I thought this would be covered by Nec. Nec Article 690 covers solar panels and generation. Nec Article 250 part X covers grounding and bonding over 1000V.
We had once engineering firm who submitted plans for public electric utility substation we told them take these...
@bwen08 you are correct it is factory installed internally bonded and from submitals xfmr when I look at HV compartment their is H1, H2, H3 terminals, gnd pad. When I look at LV compartment their is X1, X2, X3, H0/X0 terminals, gnd pad. LV compart has strap from H0/X0 to gnd pad. I have the...
Not sure what you mean by not subject to same code? I can only recommend not enforce. I am not the designer or electrical engineer of this project. AHJ reviewer contractor only can enforce NEC 2014 and which xfmr to use is not in NEC. The designer will not change to delta wye.
1.Would not some of the neutral current from xfmr still split 600V neutral is tied at bar which is grounded solidly and so is 13.2kV swbd same gnd electrode?
2. Are neutral floating? How can zero sequence current pass thru?
3. On the attachment do you see H0 terminal 13.2kV side? Note their...
I hate to say this but I am contracted reviewer for an AHJ and the previous attachment is what I came across at my desk with plans. It has not been build. I am having hard time figuring this out as well NEC code wise and how wye to wye is typically wired but any help or opinions is appreciated...
Attached sketch shows wiring from 13.2kV SWBD to 13.2kv to 600V wye to wye xfmr. Would this be something that is normal wiring for transformer such as this?https://files.engineering.com/getfile.aspx?folder=e2bc2383-9f43-4b71-97e3-34d61b3b967f&file=20191212_110108.jpg
If the 13.2kV does not come with neutral then what is MV-90 with concentric neutral cable? Also how can you make neutral to ground bond at 13.2kV switchboard. NEC 2014 Article 250.186?
I have customer owned 2000kva transformer wye to wye primary 13.2kv to secondary 600V used for solar farm. The transformer primary is fed from customer owned 13.2kV SWBD. The service point as defined in NEC 2014 is at 13.2kV Swbd which has fused disconnect to the transformer. I have 3...
