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[Allen Smith]

Ok, some of you will probably blaze me for the suggestion but here goes...  I found an adapter cable at the following link that offers a solution to ungrounded 220 outlets.

http://www.jondon.com/power-cord-adapter-50a-twist-to-30a-straight-old-style-dryer.html

I would like two kinds of feedback, opinions on the actual safety of using this and feedback regarding if it would be acceptable should an inspector show up (although I have never seen one).

[Geoff Doane]

OK, I'll bite.

It's probably better than NO ground, or maybe even a bootleg ground (ground connected to neutral).

But the ground in that 15A receptacle is likely only 14 ga. wire.  Not really big enough for a potential 30A fault current.

I'd feel better about it if it was used in conjunction with a 30A, double-pole GFCI, that would dump if there was a fault current.  This would be similar to the rule that lets you install 3-pin edisons in older homes with only 2 wires.  The first one in the string has to be a GFCI, and you have to label each one that it has NO ground.

I'm eager to hear more learned opinions. 

GTD

[Jonathan Johnson]

"Technically possible" and "safe" don't always coincide with "the inspector will approve."

Inspectors are often unlikely to approve things that a) aren't addressed by code (either specifically allowed or not specifically denied) and/or b) they are unfamiliar with. The NEMA 10-30P plug featured in the picture has been modified to be used in a manner that falls outside of its listing, so any UL listing is nullified. The green wire, which is probably just the green wire from the adapter cord continued (without break in the 10-30 plug) to the 5-15 plug, does not have a secondary outer jacket so it has no physical protection (which is required). So those are the code violations I see right off the bat.

But like Mr. Doane says, it's probably safer than no ground or a bootleg ground. Ironically, the inspector is more likely to approve a bootleg ground than THIS.

[Shawn Keck]

Safer idea then some hotel distro's I have seen!

[Stephen Swaffer]

Two major issues I see:

1. As already mentioned, undersized ground-a 30 amp circuit requires #10-even a 20 amp circuit will only be #12.

2. Requirement for ground to connect first/disconnect last.  While this adapter can be connected/disconnected correctly it can also be done incorrectly.

The dime a dozen 3 prong to 2 prong adapters also have a ground pigtail or ground tab-how many have you ever seen hooked up?  Yes, if you spend $200 on an adapter you are likely to use it-but if there is no grounded edison within a couple feet, do you have a #12 awg extension cord and can you guarantee it won't get unplugged?  As much as I hate to say it, a bootleg ground might actually be safer-you do not want a distro with a ground/neutral that are not connected somewhere (obviously usually at service).

[Tim McCulloch]

My speculation - if the 240/120v service has no ground I'd be surprised if any near-by 15/20 amp Edison outlets had a genuine EGC connection.

[Jonathan Johnson]

My speculation - if the 240/120v service has no ground I'd be surprised if any near-by 15/20 amp Edison outlets had a genuine EGC connection.

It was only a few years ago that the NEC was changed to require separate ground and neutral for ranges and dryers -- there was a bootleg ground within the junction box of the range or dryer itself, where the pigtail cord enters.. As far as I know, no other appliance was granted that now-obsolete exception. So the likelihood of a grounded 15/20 amp 120V Edison (NEMA 5-15 or 5-20) receptacle being nearby is actually quite high.

[Tim McCulloch]

It was only a few years ago that the NEC was changed to require separate ground and neutral for ranges and dryers -- there was a bootleg ground within the junction box of the range or dryer itself, where the pigtail cord enters.. As far as I know, no other appliance was granted that now-obsolete exception. So the likelihood of a grounded 15/20 amp 120V Edison (NEMA 5-15 or 5-20) receptacle being nearby is actually quite high.

I think it was around 20 years ago(or more) that neutral AND ground became an NEC requirement for clothes dryers and cooking appliances, but because so much is "grandfathered" as compliant we still see lots of 3 wire service and cord sets/connectors available for that market.  My home was built in 1956 and the "grounded" outlet for my washing machine has no actual ground hook up (and I have 3 wire 30 amp service to my dryer).  I'd submit that this is the case in many residences and more than a few old commercial installations or in jurisdictions with lax enforcement.

And I wouldn't trust a simple outlet test to verify the ground of the 15/20 amp Edison outlet.  This product violates Code and creates a potentially false sense of security that a ground connection exists when, in fact, it may not.

[David Buckley]

The real problem is halfway through the gig someone unplugs the Edison to plug an urn or phone charger in, and then there is nothing at all connected to the green wire.

[Jonathan Johnson]

The real problem is halfway through the gig someone unplugs the Edison to plug an urn or phone charger in, and then there is nothing at all connected to the green wire.

The other real problem is that if the ground is not connected first, and there is a ground fault in the equipment, then you've got a hot ground pin on that "ground plug."

[ProSoundWeb Community]