In question #13 is there a code article that states this?

Answer to Q11 in quiz does not seem to make sense. Do I understand that the "ungrouded" conductor can have white insulation? Jim

Q11. Is it legal to tape a white wire black and use it a phase conductor in a raceway?

A11. No, a conductor with white insulation can only be used for the ungrounded conductor in a raceway [200.7(C)].

No matter the Size?????

On the question about the white conductor it is a grounded conductor [neutral] not an ungrounded conductor.

Q13, If a lightning strike were to occur directly to the lightpole above a ground rod wouldnt it be a safer installation than if the nearest ground rod were 1/4 mile?

Q13, If a lightning strike were to occur directly to the lightpole above a ground rod wouldnt it be a safer installation than if the nearest ground rod were 1/4 mile?

Mike:

What's your position regarding raceway bonding of telephone system cables that carry ringing voltages in excess of 50 Vac?

Best regards, and thanks in advance,

Jonathan Kramer

You said: Q1. We are being told that we must bond our raceways containing phone cables to the cable tray when the raceway leaves the cable tray. How do we size the bonding conductor?

A1. Systems operating below 50V (such as communications systems) are not required to be grounded [250.20(A)], so there is no requirement to bond the raceways to anything.

Please explain how grounding each pole does not make it safer.

so we use some uf sleeved in a raceway to serve say a 240 volt ac unit. we tape the white black to identify the conductor. Have we violated the code?

The answer to A11 should read grounded conductor not ungrounded.

I think question 3 should be: Do I need to run parallel ground conductors in a cable tray for a 800A circuit. The phase conductors would be 2 sets of 500 or 600kcmil cables, but can you only use one 1/0 ground conductor for the egc? I say only one ground conductor is needed based on 250.122 F.

question #1 800.110

Regarding Q1 and bonding metallic raceway carrying phone cables. I believe that 250.104(B) as well as 250.4(A)(4) would require bonding this system. You argue that chapter 8 is excluded from the rest of the code by 90.3. This is irrelevant! Water piping and gas piping and structural building steel is not governed by the NEC, but they need to be bonded. The phone cable raceway IS covered by chapter 250 because it is “Other Metal Piping”, no matter what is contained within it.

I disagree with the third part of your answer to Question # 13. You state that the rod serves no safety function.

I agree that there is no requirement for a ground rod at a light pole in a commercial parking lot, however I offer the following reasons why it can be a safety issue with out a local rod attached to the poles ground stud.

1. If there is no local ground rod connected to the pole nor a ground wire down through the pole base to earth there is a greater potential for the pole to become energized by a shorted phase wire or defective ballast and remain at some voltage potential above earth. Given that the branch circuit equipment grounding conductor should prevent this by carrying the fault current to the source panel causing the overcurrent device to trip, however it is not uncommon to find the grounding conductor connections in pole bases and outside junction boxes either loose, corroded or disconnected rendering them useless. At least with a ground rod attached or other grounding earth conductor through the base to earth the pole is held at the same potential as the surrounding earth or wet asphalt that a person touching the pole would be standing on.

2.) The second reason is to safely conduct any nearby cloud or lightning induced transient voltages and current to ground. Where poles in parking lots have no individual ground rods or earth connections these transient voltages follow the branch circuit feeder path into the building to the source panel ground and in some cases will trip feeder breakers or main breakers with ground fault protection.

3.)NOTE: The solution to prevent these transients from entering the building on the branch circuit ground is to provide a path to ground at each poles. At the minimum a rod should be installed at the pole with the home run conduit. Additionally, the installation of a surge protection device inside the home run pole base in addition to the external ground rod will prevent these occurances.

I offer the above comments from my first hand experiences over many years of testing and correcting these types of conditions.

Thank you for reviewing this post and I wecome return comments,---Larry LeSueur CPQ, CBCP, Atlanta, Ga.

On question #5 To answer your question correctly the answer would be YES it does have a reference in the NEC, however FPN notes are only advisory and therefore not mandatory.

In section 110-16 pertaining to waring labels when working on energized circuits --FPN #1 refers to NFPA 70E-2004 Standards for electrical safety in the workplace. And FPN #2 refers to ANSI Z535.4-1998 Product safety sings and labels.

Regarding Q1 I understand that telephone caries 70 to 90 volt ring voltages or at least they used to. Just hold the wires and I'll give you a call. if you jump then I thing the raceway should be bonded. Anyone may certainly correct me if I am wrong since I'd like to end the requirement to bond these raceways in our jurisdiction.

typo in A11. should read grounded conductor

A solution to switch height that I did in an elementary school was to install a second set of light and fan switches below the adult height switches. ( 1 set of switches for adults and another for 1 st grade and kindergarden.) I then opened up the wall, lowered the drain pipe, and then whacked 6 or 7 inches off of the sink vanity. The children loved it because they had a set of switches and a sink that they could reach.

The complaint about handicapped access to outlets and switches is that 1 location that is not too low for ordinary people is really too high for some people. A good solution is 2 sets of stuff at 2 different heights. Actually, a room does need for some of the outlets to be at the same height as the light switches to facilitate vacuuming.

WHO ABOUT THE RULE OF THUMB THAT NO MORE THAN 300 V TO GROUND IN ONE BOX, ALSO TO SEPARATE 120 AND 277. THAT IS JUST DANGEROUS..

Q7. We are being told that the 2008 NEC now has requirements for wearing personal protection equipment. Can you show us where in the Code we can find this?

A7. The NEC is an installation standard, so it does not address personal protection equipment (PPE). all questions reguarding PPE are addressed at this site http://www.nfpa.org/

i just want to state for question 7 its in the NFPA 70E it states that anything over 50v requires gloves, glassesand a long sleeve flame retardant shirt and 277v and up requires a full body suit with full face guard and properly insulated gloves. just passing along this info

Q13. Is it acceptable to install a ground rod at the base of light poles for a commercial parking lot?

A13. Acceptable? Yes. Required? No. Does it serve any safety purpose? No.

Actually it does serve a purpose--Ohms law would show that adding even a ground rod with a given resistance in the parallel path of a fault would result in a lower impedance and therefore more current would flow clearing the overcurrent device more quickly.

A ground rod IS required at an isolated light pole IF it is served by more than one branch circuit.

A local ground rod is also useful, if installed properly, for conducting lightning current in the event the pole is struck by lightning,

Local grounding MAY, if properly done, reduce step potential, but a ground rod by itself would not accomplish this.

please remove our email from you list.

thanks

WOW I have never seen so many rebuttals or counter points about one subject, since it isn't even a code requirement ( ground rods at light poles) My E-mail is getting to full so why not lets end this topic on a high note - enough.

If I understand question 11 correctly, it asks if a conductor that is normally only allowed to be used as a grounded one can be used as an ungrounded one. The answer duplicates the question, but doesnt mention the black tape.