bonding plug adapter

[Highbeam]

Hello, I have a new Firman tri fuel 7500 genset to backfeed my house through an interlock. All permitted. The firman has a bonded neutral which I have the instructions on how to remove. That should work great for backfeed duties. However, my neighbor's well has a plug and I want to be able to power his well so I want to rebond the neutral for that use or any other standalone uses. THis is why a bonding plug was invented. My question is...

How do I build a bonding plug for such a large generator? Just use a typical duplex outlet and a 15 gauge jumper from ground to neutral? Or does this jumper carry lots of current?

Thanks.

I now see that my two 120 volt inverter gensets are different. One is bonded neutral and one is floating. I've been using both for backfeeding the house.

 

[mm08822]

There are two ways you can accomplish this.
1) Add a jumper (#14 0r #12) in a plug body between the neutral and ground. Plug this in to a 15A 120v duplex gen receptacle when not connected to the house....i.e. - feeding random loads plugged directly into gen.
2) Mount a SPST 15a toggle switch on the gen. When feeding the house, the switch is in the off position (unbonded) and in the on position (bonded) when feeding random loads plugged directly into gen.

I like the switch method as I won't loose any parts or consume a recept position.

See if the inverter gens can be modified the same way.

 

[Highbeam]

There are two ways you can accomplish this.
1) Add a jumper (#14 0r #12) in a plug body between the neutral and ground. Plug this in to a 15A 120v duplex gen receptacle when not connected to the house....i.e. - feeding random loads plugged directly into gen.
2) Mount a SPST 15a toggle switch on the gen. When feeding the house, the switch is in the off position (unbonded) and in the on position (bonded) when feeding random loads plugged directly into gen.

I like the switch method as I won't loose any parts or consume a recept position.

See if the inverter gens can be modified the same way.

Thank you. I built one using a 15 amp 120 volt duplex male plug and a leftover chunk of 10 gauge solid wire. It fits and does the bonding as you describe. I can now use this on my other inverter with the floating neutral. A switch would be awesome but more than I want to mess with.

I just have no idea how much current the jumper will ever carry. The breaker on the duplex outlet only protects the black feed to probably something like 20 amps.

The bonding jumper I removed inside the generator head was stranded with a thick insulator so I have no idea what gauge. Looked thick though.

So a little jumper, 12 or 14, on a duplex outlet is sufficient to act as a neutral bond for a 9400 peak watt genset with 50 amp and 30 amp plugs?

 

[mm08822]

If this were hard-wired in a structure, then #10 would be used for grounding. If you can fit #10 under the plug clamps, then go for it.

 

[wyliesdiesels]

Hello, I have a new Firman tri fuel 7500 genset to backfeed my house through an interlock. All permitted. The firman has a bonded neutral which I have the instructions on how to remove. That should work great for backfeed duties. However, my neighbor's well has a plug and I want to be able to power his well so I want to rebond the neutral for that use or any other standalone uses. This is why a bonding plug was invented. My question is...

How do I build a bonding plug for such a large generator? Just use a typical duplex outlet and a 15 gauge jumper from ground to neutral? Or does this jumper carry lots of current?

Thank you. I built one using a 15 amp 120 volt duplex male plug and a leftover chunk of 10 gauge solid wire. It fits and does the bonding as you describe. I can now use this on my other inverter with the floating neutral. A switch would be awesome but more than I want to mess with.

I just have no idea how much current the jumper will ever carry. The breaker on the duplex outlet only protects the black feed to probably something like 20 amps.

The bonding jumper I removed inside the generator head was stranded with a thick insulator so I have no idea what gauge. Looked thick though.

So a little jumper, 12 or 14, on a duplex outlet is sufficient to act as a neutral bond for a 9400 peak watt genset with 50 amp and 30 amp plugs?

It doesnt carry any current unless there is a fault. its sole purpose is to allow breakers to clear ground faults. that is, when an ungrounded conductor contacts a grounded/bonded object such as the generator frame. outside of that, no current is flowing on the bonding jumper under normal circumstances

 

[dave*99]

10 gauge is unnecessary in your bonding plug. The fault duration will be very short.

 

[mm08822]

10 gauge is unnecessary in your bonding plug. The fault duration will be very short.

If I already made up the plug with 14 or 12, I wouldn't go back and change it. Either will pop the breaker when a grd fault occurs.

 

[dave*99]

If I already made up the plug with 14 or 12, I wouldn't go back and change it. Either will pop the breaker when a grd fault occurs.

It’s a 15 amp plug. 20 at most. The jumper wire is an inch long…….

 

[mm08822]

It’s a 15 amp plug. 20 at most. The jumper wire is an inch long…….

Agreed, but when either a 30 or 50A circuit grounds out, the fault current will use this path in the 15/20A plug and receptacle contacts to return. This is why the switch is the better option - wire it up for worst case and all is covered. (No matter what size is used, the grd path back to nuetral is low enough impedance to trip 15/20, 30, 50A OCP.)

 

[Highbeam]

Agreed, but when either a 30 or 50A circuit grounds out, the fault current will use this path in the 15/20A plug and receptacle contacts to return. This is why the switch is the better option - wire it up for worst case and all is covered. (No matter what size is used, the grd path back to nuetral is low enough impedance to trip 15/20, 30, 50A OCP.)

I don't understand why a switch would be a better option other than ease of switching from bonded to unbonded would be easier than unplugging and maybe losing the bonding plug.

From what I understand the bonding jumper only needs to be big enough to carry the current long enough to pull the breaker in the event of a short. I used a 10 gauge (I had it and it fit) but realize that when I use it with a duplex plug, the internal wiring to that 20 amp duplex plug is likely 12 gauge. As such, I would recommend no smaller than the matching 12 gauge. The original bonding wire was much bigger and landed right on the main neutral tap from the windings.

By removing the bond my little plug safety indicator, the yellow one with three little LED lights, indicates an improperly wired circuit. It doesn't "see" the ground and doesn't like it not being bonded. Folks also have problems with those power monitors (EMS) used for RVs and floating neutral generators. RV main panels do not bond ground and neutral, it's built like a subpanel.

 

[mm08822]

I don't understand why a switch would be a better option other than ease of switching from bonded to unbonded would be easier than unplugging and maybe losing the bonding plug.

From what I understand the bonding jumper only needs to be big enough to carry the current long enough to pull the breaker in the event of a short. I used a 10 gauge (I had it and it fit) but realize that when I use it with a duplex plug, the internal wiring to that 20 amp duplex plug is likely 12 gauge. As such, I would recommend no smaller than the matching 12 gauge. The original bonding wire was much bigger and landed right on the main neutral tap from the windings.

By removing the bond my little plug safety indicator, the yellow one with three little LED lights, indicates an improperly wired circuit. It doesn't "see" the ground and doesn't like it not being bonded. Folks also have problems with those power monitors (EMS) used for RVs and floating neutral generators. RV main panels do not bond ground and neutral, it's built like a subpanel.

Your question answers itself. ....and you consume a receptacle position. (Both of which I said initially.)

A bonding jumper between neutral and ground will provide a low impedance path back to the gen and cause the cb in that circuit to trip when the hot wire contacts a grounded surface.

The original bonding wire was also sized to cover a 30 and 50a circuit. The bonding may wire have also been 37 strand or higher to handle the vibration. High strand count increases the conductor diameter. Sometimes a bonding strap is used. You were given an option to use one of the several 15/20a receptacles present on the generator to replenish the bond. (It is a workaround providing flexibility to bond/unbond as the situation arises. You wouldn't want to consume the single 30a or 50a receptacle position and loose that option for use.

If your little receptacle tester is showing a fault when the plug jumper is not installed at the gen and the tester is plugged into the generator recept (and nothing connected to the house) it is indicating the correct status. If you plug the gen into the house and feed the main panel and then test a recept in the house (or on the gen) it would read all ok.
You are testing a condition that is not supposed to be used. Permitted states are...........generator = unbonded when connected to house and bonded only when loads are directly plugged into gen. (Read the conditions I posted when you were given the 2 options.)

An RV panel (properly fed with a 4-wire cable) would be considered a load plugged directly into the gen and you would need the bonding plug installed at the gen.

 

[Highbeam]

Your question answers itself. ....and you consume a receptacle position. (Both of which I said initially.)

A bonding jumper between neutral and ground will provide a low impedance path back to the gen and cause the cb in that circuit to trip when the hot wire contacts a grounded surface.

The original bonding wire was also sized to cover a 30 and 50a circuit. The bonding may wire have also been 37 strand or higher to handle the vibration. High strand count increases the conductor diameter. Sometimes a bonding strap is used. You were given an option to use one of the several 15/20a receptacles present on the generator to replenish the bond. (It is a workaround providing flexibility to bond/unbond as the situation arises. You wouldn't want to consume the single 30a or 50a receptacle position and loose that option for use.

If your little receptacle tester is showing a fault when the plug jumper is not installed at the gen and the tester is plugged into the generator recept (and nothing connected to the house) it is indicating the correct status. If you plug the gen into the house and feed the main panel and then test a recept in the house (or on the gen) it would read all ok.
You are testing a condition that is not supposed to be used. Permitted states are...........generator = unbonded when connected to house and bonded only when loads are directly plugged into gen. (Read the conditions I posted when you were given the 2 options.)

An RV panel (properly fed with a 4-wire cable) would be considered a load plugged directly into the gen and you would need the bonding plug installed at the gen.

I understand and agree with all. Thank you.

All of my generators (inverter and noninverter) have now been converted to floating neutral and tested to properly become bonded on all receptacles when the bonding plug is inserted. I actually plan to build seperate bonding plugs for each generator to leave installed and maybe even attached to each genset with some sort of lanyard.