Off grid barn portable generator

[Tlough]

I have a barn i would like to connect to a portable generator as the sole power source. The generator is un-bonded and I understand you must bond at the first means of disconnect, in this case is the generator. If I place the bonding jumper at the generator will I need a ground rod? And will that ground rod be at the panel or at the generator? being that I am using an extension cord into a power inlet box then into the panel. Will i not use a ground rod since i am using an extension cord technically, and with adding the ground rod could cause a potential shock hazard.

 

[Dennis Alwon]

Personally, I have never seen a portable generators that was connected to ground rods.

 

[infinity]

Since the generator is not bonded why would you want to bond it? Would your barn would have the MBJ and would be connected to a GES?

 

[Tlough]

I wanted to install the bonding jumper at the gen. Since it is the first means of disconnect technically with the push button circuit breaker. Just get confused with adding a ground rod because normally generators don’t have a ground rod to keep people protected from shock. But it is a structure so it makes me think it needs one by code. But the generator is the only source of power

 

[infinity]

So the intention is the set up a SDS. The generator with a bonded neutral and connection to a GES? Then 4 wire feeder to the barn. Barn still needs to be connected to a GES.

 

[jaggedben]

In my opinion you should connect a grounding rod to the panel in the barn and also bond neutral to ground there (System Bonding Jumper). See 250.35(A). If you're being really punctillious you would also put a label on the inlet saying to only connect a generator with an unbonded neutral.

Practically speaking, the ground rod won't really do anything either way: it certainly does not create a shock hazard.

 

[don_resqcapt19]

In my opinion you should connect a grounding rod to the panel in the barn and also bond neutral to ground there (System Bonding Jumper). See 250.35(A). If you're being really punctillious you would also put a label on the inlet saying to only connect a generator with an unbonded neutral.

Practically speaking, the ground rod won't really do anything either way: it certainly does not create a shock hazard.

It really does. Without the connection to earth you can only be shocked by touching two circuit conductors. With the connection to earth you can be shocked touching an ungrounded conductor and the earth. Note this assumes a small generator where there would not be enough capacitance in the system to create a shock hazard between a circuit conductor and the earth.

Note that it would be my opinion that the premises wiring supplied by the generator would be required to be a grounded system per 250.20, so the code will require the grounding electrode.

 

[jaggedben]

It really does. Without the connection to earth you can only be shocked by touching two circuit conductors. With the connection to earth you can be shocked touching an ungrounded conductor and the earth. Note this assumes a small generator where there would not be enough capacitance in the system to create a shock hazard between a circuit conductor and the earth.

...

It isn't really the ground rod that changes that, it's the system bonding jumper.

 

[david]

Since the generator is not bonded why would you want to bond it? Would your barn would have the MBJ and would be connected to a GES?

If the source is outside a grounding electrode is required at the source location.

The system bonding jumper must be connected at the location of the grounding electrode for the source

A three wire feeder (imo) should be the supply from the gen to the building since the building is required a grounding electrode system and a system bonding jumper

 

[infinity]

A three wire feeder (imo) should be the supply from the gen to the building since the building is required a grounding electrode system and a system bonding jumper

Interesting point. The OP stated that the generator has a disconnecting means and will also have a SBJ and GEC to an electrode. Would a MBJ still be required at the barn if it were fed with a 4-wire feeder?

 

[david]

Interesting point. The OP stated that the generator has a disconnecting means and will also have a SBJ and GEC to an electrode. Would a MBJ still be required at the barn if it were fed with a 4-wire feeder?

You could run a four wire feeder

It technically would not have to be a four wire feeder. It also technically would not be a MBJ it would be a SBJ

The supply would be a 3 wire feeder with a supply side bonding jumper run with the supply conductors

Since the system bonding jumper is required at the source and the system bonding jumper is allowed at any point from the source to the first disconnect,
Your not allowed to rebond the neutral on the load side of the sbj

Except for the exception

if you have a 3 wire feeder and a supply side bonding jumper than the barn would be treated the same way you would a feeder from a service.

The neutral unbounded and the equipment ground conection to the supply side bonding jumper

 

[david]

Interesting point. The OP stated that the generator has a disconnecting means and will also have a SBJ and GEC to an electrode. Would a MBJ still be required at the barn if it were fed with a 4-wire feeder?

If it is a 4 wire feeder or a 3 wire feeder with a supply side bonding jumper the barn would be treated the same way

The system bonding jumper would only be installed at the source location

 

[david]

In my opinion you should connect a grounding rod to the panel in the barn and also bond neutral to ground there (System Bonding Jumper). See 250.35(A).

If you're being really punctillious you would also put a label on the inlet saying to only connect a generator with an unbonded neutral.

To be in compliance with 250.30 (C) and the last sentence of 230 (A) (1)

he cant do that, if the gen source is out side it has to have a bonded neutral (sbj) at the generator

Practically speaking, the ground rod won't really do anything either way: it certainly does not create a shock hazard.

 

[don_resqcapt19]

It isn't really the ground rod that changes that, it's the system bonding jumper.

It takes a connection to earth to create a shock hazard between the earth and an ungrounded conductor. The system bonding jumper creates the shock hazard between an ungrounded conductor and the conductive things connected to the equipment grounding conductor.

 

[david]

To be in compliance with 250.30 (C) and the last sentence of 230 (A) (1)

he cant do that, if the gen source is out side it has to have a bonded neutral (sbj) at the generator

250.30 (A) (1) not 230 (A) (1)

 

[Tlough]

The feed is coming out of a RV 30A outlet only 120v as well so just the single hot wire I was thinking to add the bonding jumper in the generator and drive a ground rod at the generator location for excessive fault current.

 

[Tlough]

But I wired it to a #6awg 4 wire plug for the future in case he wants to upgrade to a larger generator.

 

[jaggedben]

The feed is coming out of a RV 30A outlet only 120v as well so just the single hot wire I was thinking to add the bonding jumper in the generator and drive a ground rod at the generator location for excessive fault current.

Ground rod has nothing to do with fault current.

 

[kwired]

I wanted to install the bonding jumper at the gen. Since it is the first means of disconnect technically with the push button circuit breaker. Just get confused with adding a ground rod because normally generators don’t have a ground rod to keep people protected from shock. But it is a structure so it makes me think it needs one by code. But the generator is the only source of power

The structure does require a grounding electrode system whether supplied by service or a feeder.

Generator supply falls under art 215 o 225 much more so than 230 as it is not a service.

 

[david]

The feed is coming out of a RV

30A outlet only 120v as well

225.39 if his panel in the barn is supplying more than two branch circuits this option will not be in compliance with 225.39

But it could be a 110 volt supply.

But I wired it to a #6awg 4 wire plug for the future in case he wants to upgrade to a larger