2020 NEC : GEC and bonding screw with “emergency disconnect, service equipment”

B

B677

Member
Location
Florida
Occupation
EC
Sorry to beat a resi dead horse but I’ve recently done a third service change with this “not service equipment” variation and third inspector wanted something slightly different than the other two

First inspector had me unbond my metal water line because it might be plastic underground. I was simply bonding the metal by the service equipment and had two ground rods already. She said she doesn’t let anyone bond the waterline anymore because it’s a false sense of security. I said that if the inside still has metal this bond in theory might provide a better fault path.

Second inspector had me remove bond screw from the “emergency disconnect, not service equipment” effectively leaving that metal case of the disconnect with no fault path (PVC in and out). He tells me I can land the GEC anywhere in or upstream of the service equipment as long as it’s service rated. I took this to mean the GEC can terminate in the Emergency Disconnect, not service equipment - which is service rated but not being used as service equipment in my case. And he agreed (thoughts ?)


Third inspector tells me to put the bond screw in the “emergency disconnect, not service equipment” (I agree) and that the bare copper GEC must be extended with an irreversible splice from the emergency disconnect up 18” into the meter enclosure

Anyone able to clesr
Up with code citations ? I have one I can post relating to the GEC origination location but not sure I’m interpreting correctly

Thanks
 
B677 said:
She said she doesn’t let anyone bond the waterline anymore because it’s a false sense of security.
Click to expand...
That's not in the NEC.
B677 said:
Second inspector had me remove bond screw from the “emergency disconnect, not service equipment” effectively leaving that metal case of the disconnect with no fault path (PVC in and out).
Click to expand...
Idiot. A fault to the metal enclosure will leave it energized where someone can get killed.

B677 said:
Third inspector tells me to put the bond screw in the “emergency disconnect, not service equipment” (I agree) and that the bare copper GEC must be extended with an irreversible splice from the emergency disconnect up 18” into the meter enclosure
Click to expand...
Inspector is wrong. If the service equipment is downstream of the EM disconnect, which is not service equipment the GEC can terminate at the servcie disconnect. It's not required by the NEC to terminate as described.

Sounds like your inspectors need a refresher course.
 
infinity said:
That's not in the NEC.

Idiot. A fault to the metal enclosure will leave it energized where someone can get killed.


Inspector is wrong. If the service equipment is downstream of the EM disconnect, which is not service equipment the GEC can terminate at the servcie disconnect. It's not required by the NEC to terminate as described.

Sounds like your inspectors need a refresher course.
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Just to be clear - in the case of “emergency disconnect, not service equipment” but still using a service rated disconnect (as an emergency disconnect). Can my GEC originate from this emergency disconnect? Or do I indeed have to run it up into the meter?

I know GEC traditionally can come out of the service equipment or meter enclosure just not totally clear (thanks inspectors) if it can orginate from a service rated emergency disconnect that is strictly an emergency disconnect.

Here is my understanding why it CAN :
NEC 2020 Section 250.24(A)(1) states: "The grounding electrode conductor connection shall be made at any accessible point from the load end of the overhead service conductors, service drop, underground service conductors, or service lateral to the terminal or bus to which the grounded service conductor is connected at the service disconnecting means." The emergency disconnect is an “accessible point” on the load end of my service conductors
 
I blame the code for this. Whayyyyyyyyyyy to much confusion for something that is not rocket science. The inspectors don't agree, you try and follow the confusing code and your told by the inspectors your wrong.
 
B677 said:
Sorry to beat a resi dead horse but I’ve recently done a third service change with this “not service equipment” variation and third inspector wanted something slightly different than the other two
Click to expand...
The code section in 230 that requires the EM disconnect does not give an exception from 250.6 (A) Objectionable Current.
B677 said:
First inspector had me unbond my metal water line because it might be plastic underground. I was simply bonding the metal by the service equipment and had two ground rods already. She said she doesn’t let anyone bond the waterline anymore because it’s a false sense of security. I said that if the inside still has metal this bond in theory might provide a better fault path.

Second inspector had me remove bond screw from the “emergency disconnect, not service equipment” effectively leaving that metal case of the disconnect with no fault path (PVC in and out).
Click to expand...
Violation of 250.92
B677 said:
He tells me I can land the GEC anywhere in or upstream of the service equipment as long as it’s service rated. I took this to mean the GEC can terminate in the Emergency Disconnect, not service equipment - which is service rated but not being used as service equipment in my case. And he agreed (thoughts ?)


Third inspector tells me to put the bond screw in the “emergency disconnect, not service equipment” (I agree) and that the bare copper GEC must be extended with an irreversible splice from the emergency disconnect up 18” into the meter enclosure

Anyone able to clesr
Up with code citations ? I have one I can post relating to the GEC origination location but not sure I’m interpreting correctly

Thanks
Click to expand...
The grounding of electrical systems, circuit conductors, surgearresters, surge-protective devices, and conductive normally non–current-carrying metal parts of equipment has to be installed and arranged in a manner that will prevent objectionable current (250.6) I personally see no professional way to accomplish this with a 3-wire cable to your indoor panel and a second G-N bond. (see my recent thread)
I run all my grounding wires out to a meter/main (rebar ground, water)
The the bonding of other systems CATV, gas pipe happen out at the meter/main.
Then I run a 4-wire to the indoor panel
The indoor panel has grounds and neutrals separated just like any sub panel.
every inspector will pass this installation.
 
Relevant to the bond screw in the emergency disconnect - without it there the metal enclosure (with pvc conduit) will have no fault path and violate. The main bond happens at the service disconnect means. As far as I know The NEC does not prohibit additional N-G bonds upstream of the service equipment like it does line side.

So a main bonding jumper in the service panel and one upstream in the disconnect (to mainly provide a path for fault current for the metal case) seem logical to me
 
Eddie702 said:
I blame the code for this. Whayyyyyyyyyyy to much confusion for something that is not rocket science. The inspectors don't agree, you try and follow the confusing code and your told by the inspectors your wrong.
Click to expand...
Mind you, all the same AHJ
 
WD40 said:
The code section in 230 that requires the EM disconnect does not give an exception from 250.6 (A) Objectionable Current.

Violation of 250.92

The grounding of electrical systems, circuit conductors, surgearresters, surge-protective devices, and conductive normally non–current-carrying metal parts of equipment has to be installed and arranged in a manner that will prevent objectionable current (250.6) I personally see no professional way to accomplish this with a 3-wire cable to your indoor panel and a second G-N bond. (see my recent thread)
I run all my grounding wires out to a meter/main (rebar ground, water)
The the bonding of other systems CATV, gas pipe happen out at the meter/main.
Then I run a 4-wire to the indoor panel
The indoor panel has grounds and neutrals separated just like any sub panel.
every inspector will pass this installation.
Click to expand...
Issue here is that there are three wire dryer and range circuits with no EGC. If I used a meter main the inspector would require those circuits extend into the meter main (service equipment).

My understanding is ( I'm repeating in this thread) is that redundant N-G bonds upstream from the service equipment are not prohibited the same way they are downstream of the service equipment. The green screw in the "emergency disconnect, not service equipment" that has only PVC conduit running to it is basically to provide a fault path from the metal casing (maybe also Bond) back to its source. I don't see an engineered parallel path (remember PVC) but would someone touching the metal case have the potential to create an unintentional path for objectionable current?

I'm overthinking it but there are several hypothetical scenarios I think
 
B677 said:
Issue here is that there are three wire dryer and range circuits with no EGC. If I used a meter main the inspector would require those circuits extend into the meter main (service equipment).

My understanding is ( I'm repeating in this thread) is that redundant N-G bonds upstream from the service equipment are not prohibited the same way they are downstream of the service equipment. The green screw in the "emergency disconnect, not service equipment" that has only PVC conduit running to it is basically to provide a fault path from the metal casing (maybe also Bond) back to its source. I don't see an engineered parallel path (remember PVC) but would someone touching the metal case have the potential to create an unintentional path for objectionable current?

I'm overthinking it but there are several hypothetical scenarios I think
Click to expand...
No I don't think your over thinking it at all. I had a former firefighter turned HVAC guy tell me today "I think the EM disconnect is biggest hazard introduced by the NEC in 100 years." This was after he was finding neutral current on the CSST gas lines (see my thread)
Dangerous parallel neutral paths created by a Emergency Disconnect. A broken neutral conductor can energize the exposed metal of electrical equipment, metal raceways, gas pipe, and communications cables creating an electric shock hazard and a violation of 250.6.
It will turn properly installed CSST gas pipe into a conductor.
3-wire range and dryer circuits are bad enough as it is I would not add to that. I would just leave them connected to the neutral bar in the 4-wire sub panel, if its SE cable I'd put some white tape on the braid.
 
WD40 said:
I had a former firefighter turned HVAC guy tell me today "I think the EM disconnect is biggest hazard introduced by the NEC in 100 years." This was after he was finding neutral current on the CSST gas lines (see my thread)
Dangerous parallel neutral paths created by a Emergency Disconnect
Click to expand...
How is this any more dangerous than a bonded meter enclosure, meter disconnect, or CT cabinet ahead of the service disconnect?
 
infinity said:
How is this any more dangerous than a bonded meter enclosure, meter disconnect, or CT cabinet ahead of the service disconnect?
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For the same reason the NEC does not allow 3-wire feeders and 3-wire ranges and dryers.

'sparks' when connecting gas pipe to furnace

Did you check the neutrals at any other houses fed by this transformer and metallic water lines? When I met the POCO lineman there he checked connections and load tested, since the problem goes away when the Emergency Disconnect is shut off the problem seems to be between the Emergency...
forums.mikeholt.com
 
infinity said:
They're on the load side of the service disconnect so IMO I don't see that being very relevant to the bonding of metal parts on the line side of the service disconnect.
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The electrons dont know how to read so even if you put a sticker on it 'Emergency Disconnect' they will take all parallel paths back to the source. Also 250.6 applies either side of a service disconnect.
 
WD40 said:
3-wire range and dryer circuits are bad enough as it is I would not add to that. I would just leave them connected to the neutral bar in the 4-wire sub panel, if its SE cable I'd put some white tape on the braid.
Click to expand...
This is to be allowed, that was exactly what inspector wanted, tape the braided conductor white and leave it on the neutral. Now with 2020 three wire must originate at the service panel.

I was hoping they would allow a GFCI breaker and unbond the metal case of the range or dryer. Same concept as missing EGC from receptacles "GFCI protected, no equipment ground" Inspector thought it a reasonable solution but said "if you can find it in the code"

edit: when I say "use to be allowed" the taped braided was an inspector "solution"
 
B677 said:
I was hoping they would allow a GFCI breaker and unbond the metal case of the range or dryer. Same concept as missing EGC from receptacles "GFCI protected, no equipment ground" Inspector thought it a reasonable solution but said "if you can find it in the code"
Click to expand...
The NEC allows running a #10 green outside of the existing cable to a old range or dryer 250.130(C).
 
WD40 said:
The electrons dont know how to read so even if you put a sticker on it 'Emergency Disconnect' they will take all parallel paths back to the source. Also 250.6 applies either side of a service disconnect.
Click to expand...
The code requires everything metallic upstream of the service disconnect to be bonded to the neutral. Been that way for at least 100 years. Objectionable current is a byproduct of that requirement and with certain installations like metal raceways is permitted because it cannot be mitigated.
 
WD40 said:
The electrons dont know how to read so even if you put a sticker on it 'Emergency Disconnect' they will take all parallel paths back to the source. Also 250.6 applies either side of a service disconnect.
Click to expand...
Though on a disconnect that is isolated by PVC, and has the bonding jumper (not main bonding jumper) the case would now be bonded to the grounding conductor
B677 said:
Sorry to beat a resi dead horse but I’ve recently done a third service change with this “not service equipment” variation and third inspector wanted something slightly different than the other two

First inspector had me unbond my metal water line because it might be plastic underground. I was simply bonding the metal by the service equipment and had two ground rods already. She said she doesn’t let anyone bond the waterline anymore because it’s a false sense of security. I said that if the inside still has metal this bond in theory might provide a better fault path.

Second inspector had me remove bond screw from the “emergency disconnect, not service equipment” effectively leaving that metal case of the disconnect with no fault path (PVC in and out). He tells me I can land the GEC anywhere in or upstream of the service equipment as long as it’s service rated. I took this to mean the GEC can terminate in the Emergency Disconnect, not service equipment - which is service rated but not being used as service equipment in my case. And he agreed (thoughts ?)


Third inspector tells me to put the bond screw in the “emergency disconnect, not service equipment” (I agree) and that the bare copper GEC must be extended with an irreversible splice from the emergency disconnect up 18” into the meter enclosure

Anyone able to clesr
Up with code citations ? I have one I can post relating to the GEC origination location but not sure I’m interpreting correctly

Thanks
Click to expand...
I'm going to throw another wrench into this in relation to bonding N-G in the disconnect

Say I use the Arlington IBB that locknuts into a 1/2" KO in the bottom of my Emergency disconnect, not service equipment. There are no concentric or eccentric KOs around this 1/2" fitting.

Now I feed a #6 bare copper up through the IBB and to the neutral in the emergency disconnect. I tighten down the bare copper #GEC with the central screw on the IBB. So now without putting in the bonding screw is G-N effectively bonded in the Emergency Disconnect via the Arlington 1/2" KO IBB?
 
infinity said:
The code requires everything metallic upstream of the service disconnect to be bonded to the neutral. Been that way for at least 100 years. Objectionable current is a byproduct of that requirement and with certain installations like metal raceways is permitted because it cannot be mitigated.
Click to expand...
you know those Arlington IBB that go in a 1/2" KO ? See post #18 above. wonder what you think (I think the screw is better but the Metal KO IBB might be a non-listed bonding jumper)
 
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