2. tech-talk
  3. 1146925495

Yet another Grounding Question-Separate 'Earth'

I emailed this question to Nsgarch since he gave advice on another thread respecting the separate grounding of a dedicated subpanel, but at the risk of making some of you read yet another grounding question, I decided to post it as well. Here goes:


My electrician has installed a separate subpanel for the audio system which is 'upstream' even of the main breaker panel in the house.
It will have several dedicated lines, each with a 20 amp breaker (Square D) running separate grounds to Hubbell Hospital Grade Outlets. I was concerned about the potential 'difference' among these separate lines- one will support mid-hi-freq. amps, others, the subwoofer amps, and a third, the lower powered front-end equipment (preamp, phono stage and TT- no digital). I do have one of those Granite Audio thingies which permits me to 'star ground' everything to a single point in the system, FWIW.
But, and here's the really critical question- my electrician has proposed a pair of separate ground rods about 10' from the main ground for the rest of the house electrical system, and in his view, the audio system subpanel would be grounded just to these new ground rods, not connected, by ground or anything else, to the rest of the house. In one of Nsgarch's postings on this subject, he indicated that there could be a differential in the two different panel groundings which could put current to the 'neutral' and create a shock risk. As I understood the advice, it was to make sure that the audio subpanel shares the same 'earth' ground as the rest of the house.
Could you comment?

=====================================
128x128whart

Showing 1 response by kenyonbm

kenyonbm
141 posts
 
Whart, what is the problem (power, safety or audible) that you are trying to cure? Why do you need a separate panel? Maybe there is a simpler way.

>>By using separate or multiple grounds, the possibility exists that a short circuit may be routed away from the breaker, causing a dangerous situation.<< Only the hot side of the circut is fed through the breaker, so multiple paths back to the panel are immaterial. The current has already been through the breaker and cannot be routed away. The ground wire itself is a separate path, parallel to the neutral.

I do agree that not connecting new grounds to the exsiting panel or connecting the subpanel neutral to ground anywhere but the main panel are REALLY BAD IDEAS.

Let's talk about the underlying problem and try not to create new ones.



More to discover