Grounding in a secondary panel

[chris vis]

The Seller states "his electrician" says this secondary in the 1961 garage is okay and claims it is grounded by the conduit. (What you cannot see is this going to a 220 outlet).
I argued it required a grounding lock nut as it is a secondary. I thought they should have run a ground wire itself since this is obviously newer installation.

Thoughts?

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[Jim Port]

Continuous metallic conduit is a recognized grounding means. No special locknut required.

- - - Updated - - -

Continuous metallic conduit is a recognized grounding means. No special locknut required.

[Gunnar Alquist]

[QUOTE=Jim Port;280127]Continuous metallic conduit is a recognized grounding means. No special locknut required.

Yes, but...

It looks to me like the terminal is isolated from the panel enclosure.

Chris,

I share your concern. I often see loose set screw and locknuts. When I see conduit being used as the equipment grounding conductor, I try to notify the client that the conduit fittings can become loose and recommend tightening.

[Bill Kriegh]

Typically the ground buss would have a green screw that would indicate a connection to the box. The buss would be anchored to the insulating material so that removal of the green screw would allow the buss to be used as an isolated neutral buss.

Without "my eyes on what's there", impossible to tell if a bonding screw is present in the buss because it isn't required to be green, just usually is.

The bigger issue is how the receptacle is mounted and hooked up. Done properly, the green wire shown isn't necessary.

[John Kogel]

You could have checked for continuity between the two lengths of conduit. And conduit to the bus with the green wire.
If the supply is on a circuit breaker in the main panel, the concern is a good bond to the main panel and that is supplied by the conduit. But as Bill pointed out, we don't know how the green wire connects to the outlet, whether a wire is connected to a grounding screw at the outlet box or not. With your DMM, you could have determined if something was missing there.

You questioned it and a sparky responded. Job done.