HELP I think I have an electrical issue??


A few months ago I had 2 20amp dedicated lines with hospital grade duplex's installed. All was well with my Bel Canto Ref1000 mono's. Well a few days ago I just got a pair of Genesis m60 tube amps. I was noticing a clicking noise coming through my speakers. I first noticed this when I was just warming up the amps with no source on. Then I also noticed the clicking when a source was on with music playing.

So it turns out that the clicking noise is my electric ignition of my gas furnace, is somehow playing through my speakers (Or maybe its just one of them, not exactly sure yet) This is a very strange and annoying. If anyone has any ideas please let me know!

Tim
tmesselt
Tim, what is your understanding of an isolated ground?

Instead of hooking the outlet like you would to normal outlet.
You use a 3 wire + ground (12/3).

Black -> Power
White -> Neutral
Red w/ green tape -> Ground
Bare wire -> Ground to metal receptacle box

So what I am getting from this is that an isolated ground outlet differs from a standard, is that it the receptacle box is also grounded in addition to the outlet.

Now, that I am thinking about it, would actually hooking up the isolated ground correctly possibly help me get rid of the rf noise coming from my furnace ignition??
Tim,
Installing an IG recept on an NM-B branch circuit will not have any benefit whats so ever. Using a ferrous metal box in place of the plastic box could actually degrade the sonics of you audio system.

IG receptacles are mainly used in commercial or industrial buildings where EMI/RFI noise may be present on metallic electrical conduits, building steel structures, metal wall studs, ect, ect.
In this case for sensitive electronic equipment a IG recept may be desired.
Lets say a customer bought a piece of equipment that states the equipment must be connected to a 120V 20 amp dedicated circuit with an IG NEMA 5-20R receptacle.

First off to be a "true dedicated" branch circuit the circuit wiring can not share a conduit with any other branch circuit wiring.

So the electrician installs a 1/2" EMT, (thin wall), conduit from the electrical panel to the new recept outlet location. (Distance is short voltage drop is not a problem)
For the wire he selects #12 THHN.
(1)Black conductor, hot.
(1) White conductor, neutral.
(2) insulated green conductors.
** One green wire bonds, connects to the metal rough-in box and the other green wire connects the ground screw terminal on the IG recept.
Back at the electrical panel The black hot connects to a 20 amp breaker. The white wire to the neutral bar. And 99.9% of the time both green equipment grounding wires connect to the same equipment ground bar..... NEC will allow the ground wire that is connected to the IG recept to extend through other upstream panels,(that feed the panel that is feeding the new dedicated branch circuit), and connect the ground wire where the main feeder neutral is connected to earth.... How often do you think that happens?

Now, that I am thinking about it, would actually hooking up the isolated ground correctly possibly help me get rid of the rf noise coming from my furnace ignition??
Simple answer, no....

At this point you can't say for sure the EMI/RFI is being radiated through the air or being carried on your homes wiring... Or Both...

You would of thought the Heating and Air Conditioning Contractor would have at least sent out a tech to make sure the ignitor assembly was firmly connected to the burner assembly. And the burner assembly securely fastened to the furnace. That the ignition module grounding jumper was securely fastened to the metal structure of the furnace.

What make is the furnace. Manufacture and model number? I assume the furnace is a forced air furnace.

When you get home tonight try the gas cloth dryer...

The Midwest is full of gas furnaces with electronic ignition/ignitors.... I can't recall ever reading a thread here on Agon or AA where a member experienced your same problem.

For what it is worth My furnace is a Lennox high efficiency with an electronic ignition system. It even uses a VFD to ramp down the fan speed before shutting off after a cycle.

Audio system,
Sonic frontiers Line One preamp, tubes.
ARC VT50 power amp, tubes.

The furnace does not effect my audio system whats so ever.
Tim,
I have been following this thread with interest. I have two points:
1. Did you say that you had confirmed that your dedicated audio circuit is not on the same hot buss as the furnace?
If those two circuits are still on the same hot buss, I would be interested if moving one of them to the other buss solves the problem.
2. A simple passive power conditioner may also solve the probem. In my small cabin, one curcuit feeds my audio system as well as a laptop computer (and refridgerator). The laptop was putting noise on the line simply by being plugged in, and much worse noise when its processors were working.
A PS Audio Duet power conditioner eliminated the noise. I first plugged the laptop alone into the Duet and that worked perfectly. I then plugged the amps alone into the Duet and that worked perfectly as well. I run it that way because I can then plug the CD player/DAC into the Duet's other isolated outet. This arrangement isolates the CD player from the amps and allows for the filtering of noise from other things on the circuit (e.g. fridge).
Regards,
Charlie
So I just plugged the amps into another outlet in my living room. (This is the actual breaker for my living room and kitchen I believe.) I still got the ignition noise through my speakers.

I will try my gas dryer as soon as I can this evening and report back.

Tim
Doesn't surprize me that the furnace installer didn't come out for free. The suggestions I made in my first post can be above and beyond the manufacturer and code requirements. The installer probably did it right, but it might be better.

Be specific:
1) Make sure furnace chasis is properly bonded
2) Add heat resistant ground wire from pilot assembly (not typical) The screws that hold on the pilot are very short and a wire connector will be required.
3) Ensure ignition module is bonded (normal)
4) Bond neutral side control transformer (as opposed to floated)

There are filters that can be hard wired into the furnace but you would only require to filter the control circuit/transformer which would be no more than 40VA and not the blower/combustion fans. There are many hard wired line filters/spark quenchers that are available.

I'm not dismissing RFI but suggesting tackling the simplest solution first.