isolated ground receptacle? or...


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Old 05-20-18, 10:16 AM
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isolated ground receptacle? or...

reading my wiring book (that'll get me into trouble) about isolated ground receptacles. I produce music on the computer among other things, and I get faint electrical sounding noises thru the speakers from time to time. I also have had bad luck with thunderstorms frying my home theater amplifier, about every 3 years.
Would an isolated ground circuit to my computer ups and home entertainment ups prevent this? or would I just need a type of AC line filter?
 
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Old 05-20-18, 10:37 AM
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IG recept might help, might not. Are you sure your branch circuit is sharing ground with another circuit? If it is not, and have a plastic recept box, you may already have a IG branch circuit.

Sounds like your audio amp is sensitive to surges. Is it on a surge strip? If it already is, I would consider a UPS.
 
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Old 05-20-18, 04:46 PM
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With typical wiring methods, all residential receptacles are technically Isolated Ground. (there's a dedicated ground wire back to the main grounding point). Unless you're using metal conduit, or metal boxes on metal studs, your ground is already isolated.

I would definitely recommend a panel-mount surge protector and a high quality surge protector on your equipment. It won't catch really serious surges, but should handle most surges.
 
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Old 05-20-18, 05:05 PM
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"With typical wiring methods, all residential receptacles are technically Isolated Ground."

This is ONLY true if the receptacle is on a dedicated circuit with the cable running directly back to the applicable circuit breaker. If, as is more common, the receptacle wiring either comes from another receptacle or light fixture OR continues on to another receptacle or light fixture the EQUIPMENT GROUND is definitely NOT "isolated"


I agree with telecom guy that even with a truly isolated equipment grounding conductor it probably won't make any difference.
 
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Old 05-20-18, 07:59 PM
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How many different pieces of equipments are inter connected together in your music production setup? If there are more than one, you may have a ground loop. Lookup ground loop.

E.g. if your computer's audio out is connected to a receiver, then you have two pieces of equipments. If you also have a midi controller connected to the computer, then you have three pieces of equipments.

If it is indeed ground loop, one solution is to ground all equipments close to each other (e.g. plug them all into the same power strip), or to isolate the grounds so that the ground on equipment A does not contact the ground on equipment B. This requires using optical audio cable or opto isolators.

Of course there's also the possibility one piece of equipment is faulty and produces the ac noise on its own. Also some UPS may produce noisy power (not pure sine wave) that could come out of the speakers, so if you have an UPS, stop using it to see if makes any difference.
 
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Old 05-20-18, 08:42 PM
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A isolated ground receptacle would have two grounding paths. One would be for the metallic conduit . The other one is for the grounding prong on the receptacle .

There is no point in using one in a house wired with plastic boxes and nonmetallic cables.
 
 

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