National Electrical Installation Standards

Re: CQD answer published Monday, February 25, 2019 -Article 725 Class 2 Wiring 1) Hi Charlie: I'm taking an alternate view on the answer Chapter's 5, 7, 8, 9 in the NEC modify or amend the general rules in prior chapters. If you use a Chapter 3 covered raceway, then it must be installed and supported per the salient requirements since there's no mention of it under Article 725, Class 2 wiring. In fact, due diligence would extend to marking such raceway outlets stating that only Class 2 wiring is permitted. If metal raceways are used and part of the GEC, then all bonding and grounding is still required. The raceway needs to be intact as well. Often times, Class 2 wiring is wire-tied for support to other structures. This is a violation since wire-ties are not Listed for that purpose. Suitable straps, etc. are required and not supported from other electrical raceways, etc. Wire-ties or Tie-Wraps used outside of enclosures exposed to UV tend to get brittle and lose mechanical integrity. An example of labeling raceways to restricted type wiring can be found in Art. 504, Intrinsic Safety. The only place where you wouldn't is a Listed raceway section, such as a RMC stub, is used as a feed-though to facilitate ease of installation. Best Regards, Nick Abbatiello 2) I have been a long time viewer and a good friend of the Late Charlie Trout. He was a great person, miss seeing him and his Carole at the IAEI Western Section Meetings and I am happy to see that NECA is still carrying on his legacy. In the answer on Friday, February 22nd you referenced that there was no reference to Section 300.11 in 725.3. With Article 725 not modifying the requirements in chapter three it would appear the requirements for the raceway articles would apply. Article 725, the limited energy articles and the Chapter 8 cables usually do not require those cables to be in a raceway. It has been my thought that if a raceway is installed, than the requirements of that raceway article would apply. Thank you to NECA for continuing this valuable service. Dave
View Question & Answer

Can you build an outdoor residential service with a meter can and EMT riser through the roof and have it all rocked in. In other words, standing in front of the service all you would see is the enclosure door of the load center and the Meter face, everything else including the 2" riser conduit would be behind the rock. My thought is that you can't do that but I can't find any code in the NEC that supports that? Please e-Mail me. Clayton Walden
View Question & Answer

When a sub-panel is installed in a residential dwelling, can the grounding electrode conductor consist of the rigid conduit raceway or need it be run inside the raceway with the other conductors? Gwyneth Abell
View Question & Answer

240.4(B)(1): does this article restrict circuits with more than one receptacle outlet from using the next size breaker if the conductors are derated? Barry Yeslow
View Question & Answer

Dear CQD: Most of our manufacturing equipment is supplied by a 480V ungrounded delta system. The busways have only the three phase conductors, with no grounding conductor in the bus. The manufacturing equipment is "grounded" (?) by properly-sized equipment grounding conductors that are connected to field-installed ground lugs screwed to the metallic bus plug enclosures, using whatever type of machine screw and nut is handy (few of the bus plugs, if any, have a factory-installed grounding means in them). I don't know how the busway enclosure is grounded, but the bus plugs are clamped to the painted busway via painted clamps. Almost every machine comes from the build shop with a 120V duplex receptacle (sometimes GFCI protected), supplied by a 480V x 120V step-down transformer, and protected by a 10A or smaller OCPD (receptacle is intended for powering a programming terminal). The receptacle's ground wire AND grounded circuit conductor are both connected to the X2 of the transformer. In turn, the X2 of the transformer is connected to the backplane/enclosure of the manufacturing equipment. This is a very common arrangement is manufacturing plants. With regard to grounding and bonding, what code violations come to mind with this type of installation, for both the 480V and 120V circuits described, if any? Thanks, Wes Nichols
View Question & Answer

Apparently not everyone received last Thursdays CQD (February 28, 2019) therefore the answer to Wednesday's Question was not shared so we are re-publishing it today. Re: CQD answer published Thursday, February 14, 2019 - GFCI Location With regards to your answer on Feb 13th, how would this be different than having a receptacle in the ceiling for garage door openers? Would exception 2 to 404.8(a) apply? Bryan Berg
View Question & Answer

Re: CQD answer published Friday, February 22, 2019 Cords vs Cables I think the difference between cord and cable is one of the murkiest of gray areas in the code. After a lot of time pouring over NFPA 70 and 79, I have come to the conclusion that Cord is SJ or SO, anything else is cable. Michael Casey
View Question & Answer

Re: CQD answer published Thursday, February 21, 2019 - Re Wed Feb 20 CQD about phase conductors separated into different conduits. Your answer is perfect - and I am only accenting the excellent but easily missed concept of 300.20(B). We did this for a 3-foot long, 1600 amp, 3-Phase run between a buss-duct terminal and the machine's input box. Matching lengths of these very short conductors would have been very difficult had we not run them as lug-aligned A - B - C conduits. We used non-metallic (PVC) conduits as is necessary, BUT you must also remember to comply with 300.20(B) by cutting slots between the conduit holes if the enclosure is metallic . Otherwise that sheet of metal becomes an induction heater. Of course, full circuit-sized EGC conductors are required in each conduit. Scott Cline
View Question & Answer

Re: CQD answer published Thursday, February 14, 2019 - GFCI Location With regards to your answer on Feb 13th, how would this be different than having a receptacle in the ceiling for garage door openers? Would exception 2 to 404.8(a) apply? Bryan Berg
View Question & Answer

Re: CQD answer published Tuesday, February 5, 2019 - System Bonding Jumper Location Related to Wednesday's question, can one make the ground-grounded conductor bond in the transformer or should it be done in the disconnect? Michael Casey
View Question & Answer

Re: CQD answer published Friday, February 1, 2019 -Vehicle Showroom Classification 1) Good morning, I have run into this before. (And, no, it didn't hurt!) The issue is, the Class I, Div. 2 area in the shop area extends into the showroom when there are doorways between the two spaces unless efforts are made to prevent this. Positive-pressure ventilation is one method I have seen used. The repair shop area can also be declassified in accordance with Table 511.3(C). Placing the showroom receptacle outlets above 18" is an easy fix. If they need floor receptacles, one of the other methods would be necessary. However, if there are no openings in the demising wall between shop and showroom, there is no problem. Thanks for the forum! Grant Hammett 2) Receptacles 18" or more above floor, Thursday's question Jan:31:2019. The code section that you are looking for would be NFPA 101 Life & Safety - Ignition point. This would Not be a first here in town. 18" is the height that gasoline fumes rise to before being to heavy to fall back on itself. We have all seen switches spark or receptacles spark (when you yank a cord out especially if something is running at the time). This is an ignition/flash point. Whether it is a garage at home, repair garage, parking garage or in this case, a showroom - anywhere there could be gasoline fumes, the standard receptacle height would not be acceptable and must be over 18" off the floor. Many times, I have had an electrician tell me, "If it is not in the NEC, I am not doing it." As an inspector, we have to enforce all codes (and there are so many) no matter where it appears and will not sign off until compliance is met. As far as NFPA 70, where is the location for smokes & CO's (new and existing buildings)? The building code. Where is stair illumination (interior and exterior)? The building code. We also need to look at other areas of the NFPA, gas code (bonding), NFPA 1 & 101. Most of the time here, I see garage receptacles at three or four feet (convenience outlets) and yes, floor outlets would be a no no. I find electricity gets a bad wrap when it comes to fires, It is too easy to say it was an electrical fire. But shame on us should there be a fire and a Fire Marshal sees those receps are within the 18" range. Many times I have purchased a new vehicle and seen the staining on the ground when raining. New vehicles can leak (and stink). I would support the inspector in this case, he seems well read.Thank you for this treat every morning. Great job though I miss Charlie. Big Bad Busy Bob (or so I was called by a resident in a PB meeting)
View Question & Answer

Hi Charlie: Thanks for all you do with the code question of the day. On a recent job class 2 wiring was installed in PVC conduit to protect the wire in a wet location. Does strapping requirements apply for a conduit system if used for class 2 wiring. It is a bit grey, but it would seem to me it would. 725 does not require adherence to chapter 3 wiring methods for class 2 unless specifically stated. Thanks! Mike
View Question & Answer

What is the difference of multi-conductor cable versus a flexible cable? I use multi-conductor cables as feeders via cable tray from distribution board to panelboard. Are multi-conductor cables shall be installed in accordance with flexible cables or cords where cannot be used as substitutes for the fixed wiring of a structure? Jessie Santos
View Question & Answer

I have a short 14 foot run of 15 KV cables between medium voltage switches, Can I segregate each phase in separate conduits? Please advise Wayne Kantarek
View Question & Answer

Re: CQD answer published Thursday, January 31, 2019 - Wire Terminations 1) Charlie, I believe the question for CQD, 1-31-2019 is referring to WAGOS. They are listed for both solid and stranded wires according to the information on the package. Tom Ekstrom 2) Hi Charlie, product spec for RTRT is also interesting in regards to the question about stranded versus solid wire under "lug nuts", even though the submitter did not specify the product he was talking about. Terminals of the wire-binding screw, setscrew, or screw-actuated back-wired clamping types are suitable for use with both solid and stranded building wires. Have a great day. Greg McMurphy 3) IMHO all mechanical electrical connections are "pressure connectors" regardless of how the "pressure" is created & maintained. Crimped connections maintain continued "pressure" on the elastic deformation of metal(s). Obviously, this excludes soldered or otherwise similar metallurgical joints. Perhaps the definition in Article 100 can be more definitive (discriminating). Incidentally, you need to be complimented on the excellent job (service to the industry) you are doing giving continuity to what Charlie Trout started. R. Schneider, P.E. 4) What is meant by an upturned lug in 110.14 (A)? Josh Vinesett
View Question & Answer