Using Building Steel to "Ground" "Stuff"

[jes25]

I'm kinda the code guy around here and lately I've been asked by the account managers how to ground random objects their customers are wanting grounded. In one case it was fancy vending machine and the other a flammables storage cabinet. I know the vending machine is grounded through the EGC and the storage cabinet I don't believe needs any special external ground either. No matter, that's what the customer wants. Driving an aux rod is not practical due to the layout of the building..............So they want to just bond this building steel. I know this isn't required, but do you think it permitted? Do you think the bond wire would be required to meet the NEC rules for GEC's?

 

[infinity]

So they want to just bond this building steel. I know this isn't required, but do you think it permitted?

Yes it's permitted but as you've said not required and probably will provide little to no value.

Do you think the bond wire would be required to meet the NEC rules for GEC's?

No. It's is not a GEC. The closest thing that you may find in the NEC is a bonding jumper but there is no size requirement for that either when there is no power to the metal object. If there is something that is powered like the aforementioned vending machine then the size of the EGC run to the should be adequate for the additional bonding. Since vending machines required GFCI protection and additional bonding jumper to the steel is of limited value.

 

[winnie]

The flammables storage cabinet may require bonding to surrounding materials to bleed off static. Not part of the NEC, and not so much a connection to soil as bonding to surrounding materials.

My limited understanding is that this is an issue if flammables are being dispensed _in_ the cabinet, not simply storing sealed containers.

See:

Grounding a Justrite Safety Cabinet | Justrite

Learn the importance of grounding a Justrite safety cabinet. Discover expert insights and guidelines in Justrite's TechTALK to enhance safety practices now.

www.justrite.com

Justrites Guide to Safe Grounding and Bonding Practices

The process of bonding one or more conductive objects to the ground, so that all objects are at the same static potential as earth; also referred to as

www.justrite.com

Grounding a fire cabinet

I walk through the facility that I work in and I notice a lot of ground cables leading from the flammable supply cabinets to a metal rail that is bolted to the concrete. Or The grounding cable is run to a bolt that is is coming from the concrete to the handrails foot that is bolted to the...

forums.mikeholt.com

 

[Joe.B]

Does the cabinet store combustibles?

NFPA 30, Flammable and Combustible Liquids Code
NFPA 30A, Code for Motor Fuel Dispensing Facilities and Repair Garages
NFPA 30B, Code for the Manufacture and Storage of Aerosol Products

The List of 300+ Codes and Standards

Find, review, and buy more than 300 NFPA codes and standards—developed by technical experts and global volunteers.

www.nfpa.org

 

[Joe.B]

bonding of hazardous material storage cabinet?

Hi...I have a client who will be storing 5 gal totes of ethanol in a locked storage cabinet made for holding such material while the totes are not in use. They have asked if there are any grounding/bonding requirements for this cabinet. I have searched the NEC and have read NFPA 497 (standard...

forums.mikeholt.com

 

[augie47]

You might want to explain to those managers that 250.136 prohibits the metal frame of a building to be used for "grounding". They likely won't understand but the methods they suggest is "bonding".
_{Bonded (Bonding). Connected to establish electrical continuity and conductivity.}

 

[jes25]

You might want to explain to those managers that 250.136 prohibits the metal frame of a building to be used for "grounding". They likely won't understand but the methods they suggest is "bonding".
_{Bonded (Bonding). Connected to establish electrical continuity and conductivity.}

Well, if the steel is itself a GEC connected to various electrodes then connecting to that steel would be "grounding" what you connect to that steel. No?

Not sure I get the reference you cited:

250.136 Equipment Secured to a Metal Rack or Structure.

If a metal rack or structure is connected to an equipment grounding conductor in accordance with 250.134, it shall be permitted to serve as the equipment grounding conductor for electrical equipment secured to and in electrical contact with the metal rack or structure.

 

[infinity]

Not sure I get the reference you cited:

He's saying that in the title of your thread you used the word ground when you should have said bonded.

 

[suemarkp]

In our facilities, they usually ran exposed #6 copper to bond haz mat cabinets, racks, or other things because somewhere there is a reference that #6 or larger needs to be used where subject to damage.

 

[Joe.B]

In our facilities, they usually ran exposed #6 copper to bond haz mat cabinets, racks, or other things because somewhere there is a reference that #6 or larger needs to be used where subject to damage.

Sounds like 250.64(B)(2), but that only applies to the grounding electrode conductor. Is there something similar for bonding?

 

[Joe.B]

This is interesting and has me reviewing "Part V. Bonding" of 250 (250.90 through 250.106) and I don't see anything similar to 250.64(B)(2), but I also note that it starts off saying "Bonding shall be provided where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed." That doesn't sound applicable to this conversation.

Part VI. Equipment Grounding and Equipment Grounding Conductors starts off saying that "Metal enclosures shall be permitted to be used to connect bonding jumpers or equipment grounding conductors, or both, together to become a part of an effective ground-fault current path. Metal covers and metal fittings attached to these metal enclosures shall be considered as being connected to bonding jumpers or equipment grounding conductors, or both."

So, if someone wants to connect (bond) a metal storage cabinet to the building steel, would you call it a bonding jumper or an equipment grounding conductor? Based on the difference in language between 250.90 and 250.109, I'm inclined to thing it would be an EGC. If that's the case, then 250.120(C) would require smaller than 6 AWG to be protected as proposed in post #9.

 

[Joe.B]

Ah, I see it now, 250.102(D)(3) Protection. Bonding jumpers or conductors and equipment bonding jumpers shall be installed in accordance with 250.64(A) and (B).