Polarity/Ground Questions

I live in an older home with non-grounded electrical on the 2nd floor. The house had been remodeled and they installed GFI receptacles throughout. I would expect these to provide the necessary protection if needed. My question is related to audio equipment with grounded AC connections. Does a free-floating ground effect the proper operation of interconnects between balanced equipment?

Also all the outlets are connected to one phase. I read some years ago that it's recommended to divide up power usage between the line phases.

It would really be difficult to install new wiring so I'm wondering if it would be worth the trouble to upgrade the wiring.

On 1/6/2021 8:56 PM, Gary Vee wrote:
> I live in an older home with non-grounded electrical on the 2nd floor. The house had been remodeled and they installed GFI receptacles throughout. I would expect these to provide the necessary protection if needed. My question is related to audio equipment with grounded AC connections. Does a free-floating ground effect the proper operation of interconnects between balanced equipment?
>
There is a difference between "non-grounded" outlets and 2-pole outlets
without a separate ground. The ground in two-pole outlets is connected
to the outlet mount (the frame that attaches the sockets to the outlet
box. Houses with metal conduit and metal outlet boxes carry that ground
to the breaker box where it is tied to the common between the two phases.

When GFIs are installed in those boxes, the the ground socket is tied to
the common, often by attaching a wire to the box. The GFI will function
normally, ergo, they are safe.

If your house does not have metal conduit and boxes or does not have 3
wires going to the socket, it is still possible to make a safe, grounded
connection, but I would suggest letting an electrician to the work.

> Also all the outlets are connected to one phase. I read some years ago that it's recommended to divide up power usage between the line phases.
>
I would not recommend putting two phases into a room used for
electronics and audio. The result would be to double the voltage between
equipment on different phases. If you grab a mic connected to a mixer on
one phase while holding a guitar plugged into an amp on the other phase,
you will be immediately physically informed of the problem. ;-)

> It would really be difficult to install new wiring so I'm wondering if it would be worth the trouble to upgrade the wiring.
>
That depends on the house, and access to the wiring from room to breaker
box. Since you are asking these questions, your best option will be to
hire an electrician who can keep your house up to code.

--
best regards,

Neil

Gary Vee > wrote:
>I live in an older home with non-grounded electrical on the 2nd floor. The =
>house had been remodeled and they installed GFI receptacles throughout. I w=
>ould expect these to provide the necessary protection if needed.

This is legal and meets code. The GFI provides all needed safety and
obviates the need for a "PE" safety ground.

The GFI does not provide a common ground for RF protection, however, and that
is sometimes an issue for audio applications.

Devices that use shunt capacitors to ground for filtering (like guitar amps
and some computers) will not filter noise effectively and may pop the GFI.
If this is a problem, pull a cable and install an isolated ground outlet for
these things.

>My questio=
>n is related to audio equipment with grounded AC connections. Does a free-f=
>loating ground effect the proper operation of interconnects between balance=
>d equipment?

Not really. If anything, it's an advantage because it allows you to break
ground loops more easily.

As mentioned above, it does not keep all of your shields at the same potential
as the physical earth, and that can make low frequency noise problems worse
at times. That's a small issue in most cases.

>Also all the outlets are connected to one phase. I read some years ago that=
> it's recommended to divide up power usage between the line phases.

It is, but other outlets elsewhere in the house are on the other leg, so
on the whole they should balance out.

>It would really be difficult to install new wiring so I'm wondering if it w=
>ould be worth the trouble to upgrade the wiring.

I wouldn't upgrade it, but if you have noise problems or you are determined
to use an amp that pops the GFI, I'd pull a single cable and add another
circuit up there, with additional receptacles. I wouldn't remove the existing
ones because you can never have too many.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Thursday, January 7, 2021 at 5:54:35 AM UTC-8, Scott Dorsey wrote:
> Gary Vee > wrote:
> >I live in an older home with non-grounded electrical on the 2nd floor. The =
> >house had been remodeled and they installed GFI receptacles throughout. I w=
> >ould expect these to provide the necessary protection if needed.
> This is legal and meets code. The GFI provides all needed safety and
> obviates the need for a "PE" safety ground.
>
> The GFI does not provide a common ground for RF protection, however, and that
> is sometimes an issue for audio applications.
>
> Devices that use shunt capacitors to ground for filtering (like guitar amps
> and some computers) will not filter noise effectively and may pop the GFI.
> If this is a problem, pull a cable and install an isolated ground outlet for
> these things.
>
> >My questio=
> >n is related to audio equipment with grounded AC connections. Does a free-f=
> >loating ground effect the proper operation of interconnects between balance=
> >d equipment?
>
> Not really. If anything, it's an advantage because it allows you to break
> ground loops more easily.
>
> As mentioned above, it does not keep all of your shields at the same potential
> as the physical earth, and that can make low frequency noise problems worse
> at times. That's a small issue in most cases.
>
> >Also all the outlets are connected to one phase. I read some years ago that=
> > it's recommended to divide up power usage between the line phases.
> It is, but other outlets elsewhere in the house are on the other leg, so
> on the whole they should balance out.
>
> >It would really be difficult to install new wiring so I'm wondering if it w=
> >ould be worth the trouble to upgrade the wiring.
> I wouldn't upgrade it, but if you have noise problems or you are determined
> to use an amp that pops the GFI, I'd pull a single cable and add another
> circuit up there, with additional receptacles. I wouldn't remove the existing
> ones because you can never have too many.
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

Indeed about the number of outlets. When I remodeled my basement I should have put outlets every 2 feet instead of 6 feet or at least 4 gang outlets.