Transformer--Subpanel Wiring

Subpanel after the 5KVA transformer gives option of two 20A circuit protection, maybe three 15A circuits with a little stretch of imagination. More than that is not advised, even with a 20A 240V breaker from the main panel to the transformer. Safety first.

Generally, everything connected by analog interconnects should be on the same phase. That's not a law.

Plasma can be a large draw in itself, sometimes over 6A for the big ones. With that kind of a SMPS, probably better off not being on the same transformer. Good example of what you're isolating from.

I'm sure the electrician can figure out the subpanel.

Isolated ground? Bad idea and probably not code.

I think he means Hospital Grade Outlet

Ngjockey,

Thanks for the reply. Yeah, I'm confused and probably don't know what I'm doing. But I promise I won't begin installing until I figure it out. Safety IS first. I won't be doing any of this myself, and expect my electrician to follow code.

I really thought a 5kva xfmr would be large enough. I recall a thread where Zargon had a 4kva iso before a sub with six dedicated lines. Though I do recall that Lak had two 5kva isos before a sub, but that was to feed three different sound systems. My equipment isn't crazy big: ARC REF210s, a REF 3, and the plasma tv will draw 328 watts.

Regarding the "isolated ground"--I was going to have all the neutrals and ground wires in the dedicated lines run all the way back to the main service grounding point, per suggestion of Gs5556 in another's thread--although I don't know what this does for my sound, since they all hook together at some point.

I've collected a good bit of possible mis-information regarding grounds, and maybe you can help me sort it out: 1)I've heard of using a separate ground rod that is 6 feet from the service ground. 2)I've heard of using a separate ground rod, but bonding it to the service ground rod. 3)I've heard that the iso xfmr is a separate power supply, thus I can ground everything from the subpanel to the nearby water pipe in the utility room. 4)I've heard that isolated ground receptacles are not necessary because I have a wood frame house.

So what would be the best way to provide clean power to my gear? Thanks.

Chris

Hi Chris,

I am going through the same process with my AV power.

I have been able to get a great deal of info from not only A-gon threads but also white papers on the Jensen Transformer site (Bill Whitlock, Jensen President, has published a lot of peer-reviewed papers on grounding issues), the Ultra-K white papers from the Controlled Power site, the white papers from the Middle Atlantic Products site, the white papers from the Equi=tech site, white papers from the Ground1 site, and papers from the publications page of the Audio Systems Group site.

There is a difference between Hospital Grade Outlets (greater contact force among other benefits) and outlets with Isolated Grounds. Isolated ground duplexes separate the ground lead from the mounting strap of the duplex -- so the ground wire can be isolated from the building ground (metal boxes in the wall, other outlet grounds, etc) until the isolated ground meets up with the other grounds at the source (main panel or isolation transformer). If you check the Hubbell-Wiring site, you can check their online catalog (Hubbell Wiring Device-Kellems) and will see in section A "straight blade devices" that they make hosptal grade, industrial grade, and commercial spec grade duplexes (and explain the differences); and in section J show isolated ground versions of basic and hospital grade duplexes (plus a good explanation of isolated ground).

I believe the advice you read about isolated grounds not being needed in a wood house is because if you are already running a dedicated line (dedicated hot, neutral, ground) from the panel to your audio gear without making a stop at any other outlet or junction, then the ground is pretty much already isolated because the outlet box is nailed to a wooden stud, not a metal building frame. But I'm not an electrician, nor have I stayed in a Holiday Inn.