Outlet Question

Why do audiophiles use IG, (Isolated Ground), type outlets for the outlets to feed their audio equipment where the branch circuit wiring used is Romex? When connected to Romex branch circuit wiring IG outlets do not meet the manufacturer’s intended use of an IG outlet. In the case of Hubble IG outlets, especially the Hubbell non plated brass supporting back strap and non plated brass contacts, the IG5262 (15A) or IG5362 (20A) slender/compact design Extra heavy duty MAX outlet the IG contacts does nothing for how the outlet impacts the sound of an audio system.

The reason the outlet is used is for the neutral presentation of the sound heard from an audio system. It doesn’t color the sound nor does ’ it ’ add noise to the sound of an audio system. It’s neutral, it doesn’t get in the way of the sound... Again, it has nothing to do with the IG contact.

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FYI:

The outlet supporting back strap, that includes the threaded 6/32 hub that supports the wall cover plate of an IG, (Isolated Ground), type outlet is not electrically connected to the ground contact of the outlet. An IG outlet is not designed nor intended for use connected to Romex wiring. Though it can be wired so it will be electrically safe from a possible electrical hazard to life if the box used for the branch circuit wiring is made of metal.

Electrical safety code requires the metal box shall be grounded. So the metal box must be bonded to the EGC, ( Equipment Grounding Conductor), of the Romex branch circuit wiring. When an IG outlet is used, where the wiring is Romex, installed in a metal box the back strap of the outlet is grounded when installed, fastened, to the metal box. At that point the IG outlet is no different than a regular grounding type outlet.

A possible electrical safety shock hazard is when the electrical box is plastic. In this case only the ground contact of the outlet is grounded by the EGC. The back strap including the threaded 6/32 hub that supports the wall plate is not. IF for any reason the hot wire of the Romex comes in contact with the back strap it will be energized 120V. Imagine if the wall cover plate is metal. The metal plate will be energized 120V with respect to any grounded object. Like the grounded metal enclosure(s) of a piece of audio equipment. Even in the case where a plastic cover plate is used the metal 6/32 trim screw that holds on the plastic plate will be energized 120V.

A simple fix, but, the AHJ (Authority Having Jurisdiction) in your area may not approve it, that will ground the metal supporting back strap of the outlet.

One of these guys:

8 in. Grounding Pigtail 12 AWG Green Stranded Wire with #10 Fork/#10 Ring and Screw

How to use:

Turn off branch circuit breaker at electrical panel...

Plug in a lamp. Switch on lamp. Bulb is lit. Go to electrical panel, turn off breaker. Verify power is off...

Pull outlet from plastic wall box. Pull it out just enough to get to the green color IG ground lug screw on the outlet.

Loosen the ground screw just enough to slide the green pigtail fork behind the bare solid copper EGC ground wire. Tighten down ground screw. Make sure connection is tight. Pull on green pigtail wire.

If the outlet is a Hubbell IG outlet the 6/32x1" machine screw that fastens the Yoke of the supporting back to the wall box has an Auto Ground Clip. (Right next to the IG lug green color ground screw). Remove 6/32x1" machine screw from the auto ground clip. Remove green color machine screw from the ring, eyelet, of green grounding jumper wire. With the mechanical wire crimp of the ring facing you insert the 6/32x1" machine screw through the green pigtail ring and then into the auto ground clip on the Yoke/supporting back strap of the outlet.

Install outlet back to wall box. As for the 6/32x1" machine screw that the ground pigtail is connected to no need to over tighten the screw. Just bring it up snug as you would when installing an outlet. The auto ground clip on the outlet will make a good ground contact to the Yoke/supporting back strap of the outlet. (You can check the green ground wire ring is tight against the screw head and auto ground clip by checking the physical resistance when slightly trying to turn it back back and forth. Tighten down screw in a little more if needed.

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And then there us always the issue of what happens to your insurance coverage in the event of a fire that starts with a “non approved” outlet?

And then there [ is ] always the issue of what happens to your insurance coverage in the event of a fire that starts with a “non approved” outlet?

Can you please give an example of how a "non approved" outlet could cause a fire.

In the case of an IG, (Isolated Ground), outlet I can’t envision any instance where it could cause an electrical fire. An electrical shock hazard? Possibly if the metal supporting back strap is not grounded and became energized from contact to the hot bared conductor.

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@snapsc -- regarding insurance coverage, I've been a commercial insurance broker for over 40 years.  I know of no homeowners policy with an exclusion that voids coverage based on poor or faulty wiring.

It is common for people to confuse policy language with underwriting considerations.  For example, if an inspection reveals bad wiring, the insurance company will probably turn you down and not issue a policy, or cancel/non-renew an existing policy.  However, once the policy is issued and in force, coverage is in place until the policy expires or is canceled. The only way to void coverage at that point is if you commit an intentional act (like arson.)

Here's another example or policy coverage versus underwriting considerations -- drunk driving that causes an accident. Your auto policy will pay for the damage to your car and the damages & injuries you caused to a third party, even though drunk driving is against the law.  However, after that, your insurance company will probably cancel you and many other insurance companies will refuse to offer coverage or charge a very high price.