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mr2channel
02-04-2005, 10:07 AM
I know their is a section in the code that makes reference to grounding metal equipment racks (I.E. Middle Atlantic racks), but I cannot find it. Any of you guys know where it is in the NEC code book?

TIA

Trey

Anonymous
02-04-2005, 06:28 PM
Mr. 2 Chan.
Check NEC 645-15

Kieran


P.S. Brijaws you should be answering this post

mr2channel
02-04-2005, 09:21 PM
Mr. 2 Chan.
Check NEC 645-15

Kieran


P.S. Brijaws you should be answering this post

thanks Kieran

LarryFine
02-04-2005, 09:33 PM
645.15 Grounding. All exposed non–current-carrying metal parts of an information technology system shall be grounded in accordance with Article 250 or shall be double insulated. Power systems derived within listed information technology equipment that supply information technology systems through receptacles or cable assemblies supplied as part of this equipment shall not be considered separately derived for the purpose of applying 250.20(D). Where signal reference structures are installed, they shall be bonded to the equipment grounding system provided for the information technology equipment.

I wonder if it would be satisfactory to consider that, as long as any equipment that might energize such non-current-carrying metal parts is itself properly grounded via its power source cable(s), that said metal parts are thereby adequately grounded.

As an example, a gas furnace is considered grounded by the power feed, and this even extends to the gas supply piping. Of course, there's (usually) no harm in extra grounding and bonding most equipment, ground loops aside.

mr2channel
02-04-2005, 09:47 PM
645.15 Grounding. All exposed non–current-carrying metal parts of an information technology system shall be grounded in accordance with Article 250 or shall be double insulated. Power systems derived within listed information technology equipment that supply information technology systems through receptacles or cable assemblies supplied as part of this equipment shall not be considered separately derived for the purpose of applying 250.20(D). Where signal reference structures are installed, they shall be bonded to the equipment grounding system provided for the information technology equipment.

I wonder if it would be satisfactory to consider that, as long as any equipment that might energize such non-current-carrying metal parts is itself properly grounded via its power source cable(s), that said metal parts are thereby adequately grounded.

As an example, a gas furnace is considered grounded by the power feed, and this even extends to the gas supply piping. Of course, there's (usually) no harm in extra grounding and bonding most equipment, ground loops aside.

Thanks Larry,

The reason why I asked this question is one of my co workers did not believe me that it is code to ground our metal racks that we install. The best reason for the grounding that I can think of is if the center tap on a amplifers transformer shorts out and that transformer is chassis grounded, and that chassis is in contact with the metal rack, then there is potential for transfer to anyone who touches the rack. Anyone else have a better answer?

TIA

Trey

avzone
02-09-2005, 08:03 PM
larry,

would you say that article 640.22 would also support the grounding of av racks?

LarryFine
02-09-2005, 10:18 PM
larry,

would you say that article 640.22 would also support the grounding of av racks?Well, let's see:

ARTICLE 640 —AUDIO SIGNAL PROCESSING, AMPLIFICATION, AND REPRODUCTION EQUIPMENT

640.22 Wiring of Equipment Racks and Enclosures.
Metal equipment racks and enclosures shall be grounded. Bonding shall not be required if the rack is connected to a technical power ground.

Equipment racks shall be wired in a neat and workmanlike manner. Wires, cables, structural components, or other equipment shall not be placed in such a manner as to prevent reasonable access to equipment power switches and resettable or replaceable circuit overcurrent protection devices.

Supply cords or cables, if used, shall terminate within the equipment rack enclosure in an identified connector assembly. The supply cords or cable (and connector assembly, if used) shall have sufficient ampacity to carry the total load connected to the equipment rack and shall be protected by overcurrent devices.

I'd have to say 'yes, it sure looks that way.' By "support", are you asking if it's permissable or required? It appears that it certainly is required.

avzone
02-09-2005, 10:45 PM
yes, i was asking about article 640.22 supporting the requirement of grounding equipment racks.

thanks for the clarification larry.

djnorm
02-10-2005, 06:25 AM
Just had this happen a couple of months ago - built the rack and installed the stuff at the store, delivered it to the house, plugged it in, and got shocked by touching the rack... Turns out someone got a little over-zealous with a wire tie on an extension cord, and lit up the rack... exciting, to say the least!

avzone
02-10-2005, 07:20 AM
Just had this happen a couple of months ago - built the rack and installed the stuff at the store, delivered it to the house, plugged it in, and got shocked by touching the rack... Turns out someone got a little over-zealous with a wire tie on an extension cord, and lit up the rack... exciting, to say the least!


okay, okay, i've gotta ask...

isn't that grounds for charging extra?

:lol:

aforlano
07-26-2005, 04:20 PM
Ok, to follow up....

What is the recommended process to properly ground the rack if you are using a power surge product (i.e.: Panamax Max5100 Power Center)?

Thanks

Fred Forlano
Higher Definition