Grounding gas pipes

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GuruLal

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Question about grounding gas pipes.

1. I've realized that my gas pipes may not be properly bonded. I see some current on that gas pipe, about 2 mA or so, current is trying to go to ground via this gas pipe conduit, this is probably not Normal. If we bond this pipe, should we connect it directly to the house ground or should it be taken to the subpanel instead?

What is code and a proper protocol for bonding gas pipes.
 
GuruLal said:
Question about grounding gas pipes.

1. I've realized that my gas pipes may not be properly bonded. I see some current on that gas pipe, about 2 mA or so, current is trying to go to ground via this gas pipe conduit, this is probably not Normal. If we bond this pipe, should we connect it directly to the house ground or should it be taken to the subpanel instead?

What is code and a proper protocol for bonding gas pipes.
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Current is not trying to go to ground I assure you.

It only uses the ground to return to its source (secondary of utility transformer).

As far as I know the circuit feeding the gas appliance and a properly installed EGC is all that is needed.

No need to bond something to the electrical system unless it’s likely to become energized and/or your using it has a grounding electrode such as water pipe.
 
Unless it's CSST gas piping does not require a separate bonding conductor. Any powered gas appliances in the house will have an EGC run with the branch circuit so it is already connected to the building grounding electrode system via the EGC.
 
The code does not require any special grounding for interior gas piping. The connection of the EGC for any gas appliance that uses electricity is all that the NEC requires. The metal to metal contact between the gas pipe and the metal parts of the appliance is all that is required.
Other codes do require special bonding if you are using CSST (corrugated stainless steel tubing) as you interior gas piping.
 
don_resqcapt19 said:
The code does not require any special grounding for interior gas piping. The connection of the EGC for any gas appliance that uses electricity is all that the NEC requires. The metal to metal contact between the gas pipe and the metal parts of the appliance is all that is required.
Other codes do require special bonding if you are using CSST (corrugated stainless steel tubing) as you interior gas piping.
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It comes into home with a riser, there is a galvanized pipe that feeds into my home, but to HVAC equipment it is a flexible, insulated CSST pipe that is used.
 
GuruLal said:
It comes into home with a riser, there is a galvanized pipe that feeds into my home, but to HVAC equipment it is a flexible, insulated CSST pipe that is used.
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Where are you measuring the current?
Also 2 mA, unless you have a laboratory grade meter, is in the "noise" level and may or may not be real.
 
No, this is a high resolution clamp meter. It is as laboratory grade as it gets. Cost me over 200 bucks, they use this to diagnose electrical issues for electrosensitive people. I'm measuring that 2mA right outside the HVAC unit. My HVAC unit is a dual fuel heat pump.
 
Try running a temporary bonding jumper to the GES and then measure it again. Like Don stated 2ma is so minute it could just be an error with the measuring device.
 
GuruLal said:
the 2mA current that I'm measuring with the clamp meter shouldn't be there though right?
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No reason to think there wouldn't be some current on it.

GuruLal said:
but to HVAC equipment it is a flexible, insulated CSST pipe that is used.
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That's a connection whip, not CSST. It doesn't require anything as far as bonding.

-Hal
 
GuruLal said:
No, this is a high resolution clamp meter. It is as laboratory grade as it gets. Cost me over 200 bucks, they use this to diagnose electrical issues for electrosensitive people. I'm measuring that 2mA right outside the HVAC unit. My HVAC unit is a dual fuel heat pump.
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$200 is not even the cost of a good quality meter that an industrial electrician would use.
Please post the manufacturer and model number of your meter.
 
GuruLal said:
It comes into home with a riser, there is a galvanized pipe that feeds into my home, but to HVAC equipment it is a flexible, insulated CSST pipe that is used.
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Bonding CSST extensions to appliances is a gas & plumbing code issue, and depends on CSST insulation listing.
 
GuruLal said:
I'm measuring that 2mA right outside the HVAC unit. My HVAC unit is a dual fuel heat pump.
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Bravo on appliance selection. Heat pumps are the highest-efficiency HVAC appliances available.

Most HE appliance OEM's w/ high-frequency drives are designing for Class-2 GFCI, since required for FAU & garages.

If your meter can reliably detect HF current, and other pipes show zero, 2mA is likely a parallel value shared with EGC.

That means total current generated by appliance HF speed drive is > 2mA, but likely < Class-2 6mA by design.
 
GuruLal said:
the 2mA current that I'm measuring with the clamp meter shouldn't be there though right?
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Current flows on all parallel paths. You cannot prevent current on a grounded surface and follow the NEC at the same time.

Are you using a gauss meter to measure EMF, or are you just measuring current on conductive surfaces?
 
ramsy said:
Bravo on appliance selection. Heat pumps are the highest-efficiency HVAC appliances available.

Most HE appliance OEM's w/ high-frequency drives are designing for Class-2 GFCI, since required for FAU & garages.

If your meter can reliably detect HF current, and other pipes show zero, 2mA is likely a parallel value shared with EGC.

That means total current generated by appliance HF speed drive is > 2mA, but likely < Class-2 6mA by design.
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What is a Class-2 GFCI? There is no such class in UL 943, the product standard for GFCIs
 
ramsy said:
Thank you for the correction. Please substitute Class A for Class-2.
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The UL 943 technical committee is currently working on a change in the product standard to address the issue of the high frequency leakage currents that trip some of the Class A GFCIs.
 
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