Job Trailer Service

[transman2]

Ok, lets see if I got this right. If the electrode grounding conductor is terminated in the meter and there is a metal raceway between the meter and the main service disconnect you do not bond the grounded (neutral) bar via green screw or bond jumper to grounding terminal strip in the main service disconnect.

But, if there is a PVC raceway you do bond the grounded (neutral) bar via green screw or bond jumper to grounding terminal strip in the main service disconnect. Is that correct?

This seems confusing sometimes since you always here electricians say you must connect the grounded and grounding bar together at the first means of disconnect and then keep them separated at all panels afterwards.

 

[zbang]

Ok, lets see if I got this right. If the electrode grounding conductor is terminated in the meter and there is a metal raceway between the meter and the main service disconnect you do not bond the grounded (neutral) bar via green screw or bond jumper to grounding terminal strip in the main service disconnect.

I'm sure there are exceptions, but if the Grounding Electrode Conductor (GEC) is bonded to the neutral at the meter, then yes, you run separate N and G conductors from there. Doesn't matter whether the raceway is conductive or not. You only bond neutral and GEC once.

But, if there is a PVC raceway you do bond the grounded (neutral) bar via green screw or bond jumper to grounding terminal strip in the main service disconnect. Is that correct?

The NEC gives you have a choice of where to put that bond, at the meter or at the first disconnect. The PoCo however may not allow bonding in the meter can.

 

[raider1]

The main bonding jumper used to connect the grounded conductor to the equipment grounding conductors and service equipment enclosure must be installed at the first disconnecting means see 250.24 (B)

250.24 Grounding Service-Supplied Alternating-Current
Systems.(B) Main Bonding Jumper. For a grounded system, an unspliced
main bonding jumper shall be used to connect the
equipment grounding conductor(s) and the service-disconnect
enclosure to the grounded conductor within the enclosure for
each service disconnect in accordance with 250.28.

The grounding electrode conductor may be connected to the grounded conductor at any accessible point from the service point to the service disconnecting means in accordance with 250.24(A)(1)

250.24 Grounding Service-Supplied Alternating-Current
Systems.
(A) System Grounding Connections. A premises wiring
system supplied by a grounded ac service shall have a
grounding electrode conductor connected to the grounded
service conductor, at each service, in accordance with
250.24(A)(1) through (A)(5).
(1) General. 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, including
the terminal or bus to which the grounded service conductor
is connected at the service disconnecting means.

Chris

 

[don_resqcapt19]

I'm sure there are exceptions, but if the Grounding Electrode Conductor (GEC) is bonded to the neutral at the meter, then yes, you run separate N and G conductors from there. Doesn't matter whether the raceway is conductive or not. You only bond neutral and GEC once. ...

Even where the neutral is bonded at the meter, you are required to bond it at the service disconnect. The grounded conductor is used for both the grounded and the grounding conductor on the line side of the service disconnect. Separate grounded and grounding conductors are not installed between the meter and the service disconnect.

Yes, where the conductors between the meter and the service disconnect are in a metallic raceway, that raceway is a parallel path for the neutral current and is permitted by the code.

If the meter is a "meter main" then the service disconnect is at the meter and you would need to install separate grounded and grounding conductors from the service disconnect to the panel.

 

[transman2]

Even where the neutral is bonded at the meter, you are required to bond it at the service disconnect. The grounded conductor is used for both the grounded and the grounding conductor on the line side of the service disconnect. Separate grounded and grounding conductors are not installed between the meter and the service disconnect.

Yes, where the conductors between the meter and the service disconnect are in a metallic raceway, that raceway is a parallel path for the neutral current and is permitted by the code.

If the meter is a "meter main" then the service disconnect is at the meter and you would need to install separate grounded and grounding conductors from the service disconnect to the panel.

Thanks !!!!

 

[zbang]

Don is, of course, correct. I should know better than to post before the coffee kicks in. Which I am now doing anyway .

 

[augie47]

A fairly common problem I encounter is folks that connect the grounding electrode conductor in the meter then route it through the nipple into the service disconnect and bond it in the service disconenct also, thus having a parallel path between with the neutral and grounding electrode conductor.

Also, it is often overlooked by inspectors locally but, IMO, if you route the GEC thru a metal nipple into the service disconnect you would need to bond each end of that nipple to the conductor per 250.64(F)

 

[JDB3]

}}If the meter is a "meter main" then the service disconnect is at the meter and you would need to install separate grounded and grounding conductors from the service disconnect to the panel. {{

By meter main, are you referring to the meter & disconnecting means being in the same enclosure?

One power company around here, sets their combination meter/disconnect on their pedestal & leavs the rest to us. There is no place for a grounding conductor in this set up. AND the distance from the bottom of the enclosure to the bottom of the breaker (where the wires attach) is perhaps 6 inches. Makes for fun getting you 4/0 Al. wires connected to the lugs on the breaker. hmy:

 

[david]

The title of the post is Job trailer Service. Wouldn't article 550 be the correct article and wouldn't the bonding be required to be at the service disconnect with an insulated equipment ground run from the service disconnect to the Job trailer distribution pane?