Something we always did,,,,,,,,,,,

[dicklaxt]

,,,,,,,,,,as a matter of routine way of doing things.

That was to use the ground conductors within a multiconductor tray cable as a return fault path from the equipment being served to the ground bus in the MCC.This was then extended to the transformer via cable bus or bus duct.When RMC was used a ground conductor was always pulled with the user conductors,,,,the conduit was not used for fault protection.

You know when you do something for 44 years it just becomes automatic whether it was spec'ed,an NEC requirement/recommendation or IEEE recommendation etc.

In reading over the many posts both residential and commercial on this and other forums it appears that the conduit was most often used for this purpose.I realize most of you folks are sometimes a one man operation and /or a small crew and material dollars would bend the allowed contract dollar.I normally didn't have to address that as the contract was bid and won to do as described above.

Now with all that being said I can't find a requirement thus far in looking in the NEC that requires this.It must be there somewhere or the cable manufacturers would not be putting those ground wires in the majority of standard cables.

I certainly feel as you do I'm sure, that a continuous cable from fault to voltage source is a more positive application of providing fault protection.

Where's the requirement written in NEC ?

dick

 

[iwire]

Many areas still do not instal wire EGCs within EMT, IMC etc.

Also both AC cable or MCap cable utilize the armor as the grounding means. Both of these cables are still in use. As a matter of fact MCap is a recent invention.

See 250.118 for a list of acceptable grounding conductors.

 

[dicklaxt]

Many areas still do not instal wire EGCs within EMT, IMC etc.

Also both AC cable or MCap cable utilize the armor as the grounding means. Both of these cables are still in use. As a matter of fact MCap is a recent invention.

See 250.118 for a list of acceptable grounding conductors.

I'm with you on all of the above ,my question was where is it written, if it is, that an EGC must be provided for fault protection whether it is in a multi conductor cable or singles in conduit? I don't think it exists tho is the preferred method in tray systems.

I suppose the advent of cable tray usage 50 yeasrs ago pushed the EGC within a multi Tray Cable to fall on the manufacturer's ear and they better step up to the plate or lose the game.

dick

 

[kwired]

I think you have no doubts an equipment grounding conductor is required, but are questioning what is allowed to serve as the equipment grounding conductor.

Take a look at 250.118.

Pretty much all metal raceways are permitted to be used as EGC in most cases, as well as gutters, wireways, cable trays, and other metallic equipment used to contain conductors, certain equipment may have limitations to length, or maximum overcurrent protection allowed.

 

[dicklaxt]

Like I said I understand the requirements as you say (kwired) and what(Iwire)said my original question also rewritten in my 2nd response has still not been answered,,,,,,

Once again is there a written requirement in the NEC that says you must use the ground wires in a multi conductor tray cable for a ground fault return and further does it say an EGC must be pulled into a conduit and used for a ground fault return in lieu of the conduit.

I'm not asking "can it be used",,,, but,,,, "must it be used".

dick

 

[kwired]

Like I said I understand the requirements as you say (kwired) and what(Iwire)said my original question also rewritten in my 2nd response has still not been answered,,,,,,

Once again is there a written requirement in the NEC that says you must use the ground wires in a multi conductor tray cable for a ground fault return and further does it say an EGC must be pulled into a conduit and used for a ground fault return in lieu of the conduit.

I'm not asking "can it be used",,,, but,,,, "must it be used".

dick

I would have to look at the cable tray issue harder, but for the metal raceways - you don't need a separate EGC - the raceway is a suitable EGC. Now if you decide to pull a grounding conductor anyway you must bond it to boxes and enclosures it passes through (exception is if the other conductors do not contain junctions or splices).

 

[RUWired]

,,,,,,,,,,
Where's the requirement written in NEC ?

dick

Is this what your asking and looking for??

336.10 Uses Permitted.
Type TC cable shall be permitted to be used as follows:
(1) For power, lighting, control, and signal circuits.
(2) In cable trays.
(3) In raceways.
(4) In outdoor locations supported by a messenger wire.
(5) For Class 1 circuits as permitted in Parts II and III of Article 725.
(6) For non?power-limited fire alarm circuits if conductors comply with the requirements of 760.49.
(7) In industrial establishments where the conditions of maintenance and supervision ensure that only qualified persons service the installation, and where the cable is continuously supported and protected against physical damage using mechanical protection, such as struts, angles, or channels, Type TC tray cable that complies with the crush and impact requirements of Type MC cable and is identified for such use with the marking Type TC?ER shall be permitted between a cable tray and the utilization equipment or device. The cable shall be secured at intervals not exceeding 1.8 m (6 ft). Equipment grounding for the utilization equipment shall be provided by an equipment grounding conductor within the cable. In cables containing conductors sized 6 AWG or smaller, the equipment grounding conductor shall be provided within the cable or, at the time of installation, one or more insulated conductors shall be permanently identified as an equipment grounding conductor in accordance with 250.119(B).

 

[hillbilly1]

Most of our large customers have it in the specs, where they require a ground pulled regardless of conduit type. Some actually visually and physically check to make sure you are following their specifications.

 

[kwired]

Dick, are you specifically asking about tray cables or just cables in general?

I am not all that familiar with cable trays, and tray cables, but for cables like AC, MC, NM, UF, they have to include the EGC within the cable or make the sheath a qualifying EGC otherwise there is often no other EGC path to use like there is with a metal raceway.

 

[dicklaxt]

I retract the question.



dick

 

[don_resqcapt19]

...Once again is there a written requirement in the NEC that says you must use the ground wires in a multi conductor tray cable for a ground fault return

Yes, the code requires that the EGC be in the same cable as the power conductors when a multiconductor cable is used. (note some cables have their metal jacket listed as an EGC and would not require an EGC of the wire type within the cable) 300.3(B)

and further does it say an EGC must be pulled into a conduit and used for a ground fault return in lieu of the conduit. ...

There is no code requirement that an EGC of the wire type be used with any raceway that is listed in 250.118 as an EGC.

 

[dicklaxt]

Thanks Don, thats the answer I was looking for ,I knew we had to have been doing it for some reason LOL Tghewre4 are a couple of exception but they are not part of the question ,thanks again

dick