2. misc-audio
  3. 172453-20253

Star Grounding and the Home

This comes up a bit so I wanted to talk about it.

 

You may not, for safety reasons, create a separate grounding scheme for appliances fed from the same service. May. Not. Ever. That means that at the service entrance all the grounds and the neutrals must connect, preferably with zero Ohms between them and zero Ohms to the ground rod(s). I say preferably because, corrossion, splices, etc. These are rarely perfect.

 

However, you MAY run an insulated separate ground wire to the ground rods which feed the rest of the home. This is like a star grounding scheme in a piece of audio gear. You meet the code criteria, and you hopefully dissipate noise in the ground wiring of your home at the rod before it can reach your gear. You can achieve a very good version of this by running a sub panel to your audio room.

 

One interesting possibility that I’ve seen some power conditioners hint at is to use a coil with appropriate gauge wiring and low DCR to isolate the gear. This meets the code requirements that it can carry 100% of the current in the event of a short, and the coil blocks noise from the rest of the home. Pricey, cause it requires heavy coils, and because.... audiophiles.

erik_squires
oldhvymec
5,101 posts
 

In the mid west and Sierra's where there a lot of lightning strikes you can have 20 ground rods hooked to lightning rods they just all have to be bonded together, same for your stereo system.

This is on the principal of marine grounding. We called it a star marine ground but it is pure marine tech.. Try fixing noise issues on a houseboat plugged into a dock AC supply..It's ALL marine ground (star). The boat is fiberglass, but you still have to share a common ground with an onboard generator, appliances and DC water pump motors.

Everything has to run it's own ground wire and it cannot be broken or spliced unless it's in an explosion proof box. You can use a common block but it needs to be bonded also to the hull if it metal.  In brackish water (the ocean is a hugh battery) You need something for the electrolysis to EAT other than the metal on the boat. Grounding bars!! AWAY from your onboard star points. ALL threads have to use Never-sieze.

I worked on sea going rescue Tugs and fishing boats every now and then for Cat.. They can't break and they can't catch on fire.. What puke buckets.. Working in rolling seas in a foot of bilgewater and friggin' rats askin for something to eat. YUP I miss that job.

I hate seals too, they are mean.. Look at the cute seal, sea going squirrels if you ask me.. Fisherman hate um..

erik_squires OP
16,212 posts
 

Maybe i have misunderstod, but here in Denmark we can have 2 ground rods. One for the house installation and one for the hifi (if made correctly)

 

In the US you can have as many ground rods as you want. The trick is that they must be electrically bonded together.  The issue is life-safety and that the +- 120 VAC is referenced to it.  If you have a different ground, it's no longer the zero point, and when a short occurs you are no longer guaranteed it will be at 0.

thankful
223 posts
 

What about devices like the Puritan Audio Labs grounding Master?

You drive a second grounding rod in the ground and run a wire from that rod to the Puritan Audio Labs grounding Master and from the grounding Master to the ground on their conditioner. Are there any issues with this?

Thanks

 

 

 

 

Ag insider logo xs@2x
cleeds
5,967 posts
 
erik_squires

 

In the US you can have as many ground rods as you want. The trick is that they must be electrically bonded together ... If you have a different ground, it’s no longer the zero point, and when a short occurs you are no longer guaranteed it will be at 0.

Here's the issue: All ground rods must be bonded together, and then bonded with the neutral at the main service panel. Otherwise, a fault sent to ground would not trip the breaker, which creates an obvious hazard.

jea48
4,469 posts
 

@erik_squires Said:

If you have a different ground, it’s no longer the zero point, and when a short occurs you are no longer guaranteed it will be at 0.

In the event of a Hot 120V ground fault to an isolated dedicated ground rod the voltage WILL NEVER be zero. The Step Potential voltage around the ground rod could be as high as 120Vac.

The return path for the 120Vac ground fault current travels through the ground rod, through the earth, back to source, the Utility Power Company’s power transformer’s grounded neutral conductor. There are multiple paths provided through the earth for the ground fault current to travel back to the power transformer’s grounded neutral.

* Through the earth to the grounding electrode system of your home to the grounded neutral conductor in the electrical service equipment panel back to the source.

* Through the earth to the Utility Power Company’s driven ground rod at the transformer for connecting the neutral to earth.

* Through the earth to any of your neighbors grounding electrode systems to the grounded neutral conductor in the electrical service equipment panel back to the source.

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