Grounding appliances directly to structural steel in residential units?

[Matt Donovan]

I was shocked to look into the distribution panel in my newly constructed NYC apartment unit and see no grounding run with any branch circuits. The 208v split phase 3W feeders supplying the 125A panel come in with an appropriately sized ground terminated to a bus, but that bus is otherwise empty. This is a commercial building with a steel structure. Is it possible that my appliances are bonded directly to the steel structure? If so, what section of code permits this? If not, I am extremely concerned that my water heater, HVAC, fridge, washer/dryer, receptacle, are not properly grounded...

 

[augie47]

What wiring methods are being used ? (Conduit/AC cable ?).
It's possible the wiring method is serving as the equipment ground per 250.122

(structural steel may not be used as the equipment grounding means 250.136)

 

[electricalist]

If you check a plug or wiring to an appliance with a volt meter. Hot to neutral , hot to ground neutral to ground ,,what do you get?
There a as many ways to assume every thing is (grounded) has an equipment ground as there are to assume there isnt.
Did you hire a licensed electrical contractor and did the work pass inspection?

 

[SceneryDriver]

In NYC, Romex isn't widely used, and depending on the building type and height, isn't allowed. Therefore, AC cable is very popular. AC's jacket is rated for use as the grounding conductor, and does not have a green wire in the cable. When used with listed fittings, the aluminum bonding wire is simply cut off when the jacket is stripped. Assuming metallic boxes were used, that's all the grounding you need. You would see a green wire if MC cable was used, as its jacket is NOT rated to act as the grounding conductor; the green wire would be landed on the ground bus and connected to device(s) on the other end.

As an alternative, your apartment may have been wired in EMT, where the conduit is rated for use as the grounding means. As with AC, you would only have grounding jumpers at the devices, if required.

There's a chance that you're right; people do stupid things and someone may have tried to use the structural steel as a grounding means, but that sounds unlikely especially because you mention it's new construction.


SceneryDriver

 

[electricalist]

Keep in mind the bldg steel is probably bonded to the service equipment that feeds the bldg and that you may find it electrically connected to your panels grounding bus but thats to ensure an effective path back to the source in the event of a fault.

 

[Matt Donovan]

Looks like AC cable

Looks like AC cable

Thanks everyone. I hadn't know about type AC cable, but the neutral conductors are printed with "Armor is equipment grounding path component", so I'm guessing it's type AC. I still don't know if they used proper fitting to bond to the panel frame, but I'll give them the benefit of the doubt. I copied a couple photos. I checked, and there is good continuity between receptacle and panel ground. It was the water heat and HVAC that had me worried.

FYI, tenants in this building are getting astronomical utility bills (like, >$1000/mo for a 2br), so I looked into the wiring and voltages just for kicks.

 

[electricalist]

See its not the electrician who needs to be hunted down its the poco. What circuits are the arc fault breakers feeding if you dont mind? Bedrooms,

 

[Little Bill]

Thanks everyone. I hadn't know about type AC cable, but the neutral conductors are printed with "Armor is equipment grounding path component", so I'm guessing it's type AC. I still don't know if they used proper fitting to bond to the panel frame, but I'll give them the benefit of the doubt. I copied a couple photos. I checked, and there is good continuity between receptacle and panel ground. It was the water heat and HVAC that had me worried.

FYI, tenants in this building are getting astronomical utility bills (like, >$1000/mo for a 2br), so I looked into the wiring and voltages just for kicks.

That is a subpanel. The neutral and grounding conductors are isolated from each other.
The green EGC (equipment grounding conductor) is ran to the ground bar that is in direct contact with the metal of the panel. Thus the whole cabinet of the panel is bonded to the grounding conductor. The connectors are the right type. They also make contact with the metal of the panel so any circuits ran in the AC cable are grounded.

Also, you can't go 100% by it being new construction that everything is right, but since this is in a larger city I would bet it was inspected and passed accordingly.

Another also: the > $1000 a month is called "welcome to winter in NYC"!