I’m nearing completion on my new audio listening room. Since it was built in an unfinished basement where I had easy access to the power panel, I followed the suggestions of many (including on this forum), including:
• Dedicated sub-panel for audio room only
• Specialized low-impedance 20-amp breakers
• 10 AWG wire
• Special outlets (PS Audio)
• Isolated ground
It is about the latter that I just read something on another forum:
“Isolated” in this context means simply that there is a dedicated (“isolated”) ground wire from the outlet terminal ground running directly to the building ground conductor terminal. Nothing scary here.
Isolated ground does not mean running the ground wire to a separate unbonded grounding rod. This is dangerous as differences in voltage potential between the building ground and this additional ground can be quite high."
But this is exactly what I did - I ran a dedicated ground wire from the Sub-panel to a grounding rod outside. Since the sub-panel is ONLY for the audio room, I figured that I could just use the grounds in the Romex 10AWG, then ground everything to the new ground rod. The new sub-panel is not sharing the same ground as the main house panel. Is this dangerous or a mistake in some way? If I act fast, I could re-do the ground from the outlets directly to the ground rod, then ground the sub-panel to the main panel. Thanks much!
You definitely need to seek a local licensed electrician, for what you are proposing does not meet adequate bonding with service and more than likely violates electrical code in your area.
Thanks, so if I went conservative with the sub-panel - grounding it to the main panel so it shares the main house ground, and pull isolated grounds from the audio room outlets only to the new ground rod, would that be OK? For years I’ve read about people choosing to ground their audio equipment directly to a water pipe - how would that be any different?
There should be only one ground.
Neutral and ground are bonded at the main panel. The return from the subpanel is “grounded” through the neutral. Thus if you add any additional ground to the subpanel in any way you are creating a dangerous condition as well as a good possibility of a noisy ground loop.
Get a good electrician involved in your project
@Elk is right, an audiophile friend of mine also ran a sub-panel 20 feet away from the main and punch in a separate ground rod right outside his listening room. The sub-panel’s ground is tie to the main panel’s ground with a proper size ground cable and also bonded to the separate new ground rod. If you don’t bond this separate rod to the sub-panel, first of all it is again code and second, you can like Elk said created a noisy ground loop, very undesirable, and third, it is not an adequate ground. The main water pipe by code should be bonded to the main panel no greater than 5 feet from entrance of house. The ground and neutral should be bonded only at the main by code and to prevent ground loops.
Hi Elk (and waymanchen11 whose reply arrived as I was typing), thanks for the reply. In further research, here’s what I found, so hopefully this will be good information for others who might be tempted to make my mistake based on what they’ve read about Isolated Grounds. First, there are two types of grounding at play here that may or may not be related. The first, and obviously most important is the grounding that’s done for safety reasons. This involves the ground from the boxes and wires going to the breakers, including the box that holds the innards of your audio equipment. This ground needs to go to the same ground-point as the rest of your house. So what I need to do is simply add a line from my new ground rod to the other ground rod, to make sure there is no difference in potential between the two grounds. There’s a slight possibility I might benefit in some way by having the ground outside the rest of the system, but either way, safety and code are ensured. The other type of ground is the one on the back of your equipment that deals with grounding that goes on inside. If this one is “lifted” to a separate isolated terminal, it is meant to be experimented with to help deal with ground loops. That ground isn’t likely to cause a serious shock. I am no electrician, but this seems to be what’s supposed to happen.
Check and see if what you intend to do is within code. The code is required for good reason and if something should happen to your equipment, you may be compensated by insurance. By all means, if there is no code violations, go for it. I really believe the difference in the sound to your system is negligible if at all from a properly grounded system. Just my thoughts.
Note that having grounding rods in series will at least improve your ground impedance. If you want to take this further, you might want to consider watering your ground rods with mineral water - there is an extensive thread here called “Do you water your ground rod?”
You can pound in as many ground rods as you like, as long as all the ground rods are tied together using proper sized wiring and methods. For example, most every installer in my market expects to see a ground rod specified at every exterior light pole. It’s not a requirement but the idea is to provide a path for lightning if the pole is struck. My theory (everyone has a theory on grounding) is that this is a lot of work and money over nothing but my company specifies them because I don’t want to answer 1000 questions about why there isn’t a ground rod at every light pole. All of those ground rods (some parking lots have a lot of light poles) are interconnected through wiring or metallic raceway and connected, eventually, back to the main service grounds: ground rod grids, cold water mains, structural steel, foundation rebar, ufer grounds bla bla bla.
For the record, my modest American suburban home has one 8’ ground rod and a single connection to the street side of the copper water main (and a jumper across the meter) and I don’t think about it any further. I do not water my ground rod!