Is a neutral required?

[ryanpickett2003]

Good Morning.

I have a parking lot being fed with a 100 amp service. The utility company is requiring me to set the service pole at the highway. The problem is I now must set another panel which will control the lights and I will set my contactors there also. The sub-panel will be 1000' run and to accomadate for VD I'm installing 500 MCM AL. All lighting will operate on 240 volts. Do I have to have a neutral to that sub-panel and If I do, how do I size it for the distance?

Thanks for the help.

 

[Dennis Alwon]

If the equipment does not require a neutral then one is not required at the sub panel however it may behoove you to install one as it may be needed later. The neutral cannot be smaller than the equipment grounding conductor.

Also look at 250.122(B)

 

[cpinetree]

Will the contactor feed the panel? or is the panel feeding the contactor and then the lights?

If the contactor feeds the panel I do not think a neutral is required, especially if you use a panel with exactly the correct spaces for the number of 2 pole breakers you have feeding lights.

I think if you feed the panel first and you have additional spaces available you will need to run a neutral. However you will only need to size the neutral for the neutral load, accounting for voltage drop and not smaller than the ground.

It may be best to size the panel with exactly the number of 2 pole breakers you need, and label it a 240v panel only no 110v loads.

Of course next year they will want 110v recpts for Christmas lighting, and you will have to set a transformer along with a subpanel / larger panel.:happyyes:

and what Dennis said ->
If the equipment does not require a neutral then one is not required at the sub panel however it may behoove you to install one as it may be needed later. The neutral cannot be smaller than the equipment grounding conductor.

Also look at 250.122(B)

 

[iwire]

There is no way we would bring a neutral 1000' on the chance someone might need it later.

It would be more cost efficient to add a transformer for any future 120 loads.

Heck it might even be more cost efficient to buy two transformers, one to kick 240 up to 600 volts and another to bring the 600 volts back down to 120/240 at the panel.

This would greatly reduce the wire size needed to get 1000' away.

 

[Dennis Alwon]

There is no way we would bring a neutral 1000' on the chance someone might need it later.

It would be more cost efficient to add a transformer for any future 120 loads.

Heck it might even be more cost efficient to buy two transformers, one to kick 240 up to 600 volts and another to bring the 600 volts back down to 120/240 at the panel.

This would greatly reduce the wire size needed to get 1000' away.

That's good advice...:thumbsup:

 

[Cavie]

Will the contactor feed the panel? or is the panel feeding the contactor and then the lights?

If the contactor feeds the panel I do not think a neutral is required, especially if you use a panel with exactly the correct spaces for the number of 2 pole breakers you have feeding lights.

I think if you feed the panel first and you have additional spaces available you will need to run a neutral. However you will only need to size the neutral for the neutral load, accounting for voltage drop and not smaller than the ground.

It may be best to size the panel with exactly the number of 2 pole breakers you need, and label it a 240v panel only no 110v loads.

Of course next year they will want 110v recpts for Christmas lighting, and you will have to set a transformer along with a subpanel / larger panel.:happyyes:

and what Dennis said ->
If the equipment does not require a neutral then one is not required at the sub panel however it may behoove you to install one as it may be needed later. The neutral cannot be smaller than the equipment grounding conductor.

Also look at 250.122(B)

Code # please

 

[cpinetree]

Code # please

I think if you feed the panel first and you have additional spaces available you will need to run a neutral.

I knew I should not have answered before coffee, and being to lazy to crack the book.:weeping:

Please disregard all comments made before 7:30am

 

[mjf]

There is no way we would bring a neutral 1000' on the chance someone might need it later.

It would be more cost efficient to add a transformer for any future 120 loads.

Heck it might even be more cost efficient to buy two transformers, one to kick 240 up to 600 volts and another to bring the 600 volts back down to 120/240 at the panel.

This would greatly reduce the wire size needed to get 1000' away.

hahaha....made me think about the fact that we must now provide a neutral in switch boxes because "someone might need it later". How many code cycles will elapse before politics require a neutral in the OP's scenario?:slaphead:

 

[John120/240]

hahaha....made me think about the fact that we must now provide a neutral in switch boxes because "someone might need it later". How many code cycles will elapse before politics require a neutral in the OP's scenario?:slaphead:

In the OP's situation it is a different situation. The reason for a grounded conductor in every switch box is because people were using the grounding conductor for a return path. Occupancy sensors come to mind.

 

[mjf]

hahaha....made me think about the fact that we must now provide a neutral in switch boxes because "someone might need it later". How many code cycles will elapse before politics require a neutral in the OP's scenario?:slaphead:

In the OP's situation it is a different situation. The reason for a grounded conductor in every switch box is because people were using the grounding conductor for a return path. Occupancy sensors come to mind.

Yes, I do understand that these are totaly different situations. The "somebody might need it later" point remains.

People install ceiling fans to just about anything. Should ALL ceiling boxes be required to be fan rated?

 

[jap]

Sounds like someone needs to redesign the Electrical for the parking lot.

1000' to anywhere when it requires this size of conductor for voltage drop on a 100a Feeder is rediculous.

 

[Cavie]

Yes, I do understand that these are totaly different situations. The "somebody might need it later" point remains.

People install ceiling fans to just about anything. Should ALL ceiling boxes be required to be fan rated?

No, the box can be changed. Wireing, a little bit tuffer.

 

[mjf]

No, the box can be changed. Wireing, a little bit tuffer.

tuffer for who? the customers bank account?

the fact remains, the same people that would use the grounding conductor as a return path are the same ones that are installing ceiling fans that will fall on your head.

 

[Cavie]

tuffer for who? the customers bank account?

the fact remains, the same people that would use the grounding conductor as a return path are the same ones that are installing ceiling fans that will fall on your head.

So, your saying I should have a fan rated ceiling box in my 3' x 6' hallway or my bedroom closet etc?

 

[jap]

i think he's saying the exact opposite.
If you need it, install it, if you dont need it then dont put it in just because the next guy might need it,at least this is the way I'm understanding him.

 

[don_resqcapt19]

In the OP's situation it is a different situation. The reason for a grounded conductor in every switch box is because people were using the grounding conductor for a return path. Occupancy sensors come to mind.

Lets be clear about the code rule requiring the grounded conductor to be run to light switch locations...it was the manufacturers that triggered this change not the installers. The manufacturers were making devices that used the EGC as a grounded conductor.

 

[jap]

So who eventually figured out that they were using the EGC as the Neutral conductor when thier device was attached to the wireing system?

Was the conductor coming off of thier device white or green? and why wasnt a stop put to that when it was discovered ?

The new rule does nothing to fix the thousands of installs where voltage is now beind applied to the EGC even after all of the trouble we go through to stop it.

If the wire color coming off of thier device was white but the instructions said to connect it to the EGC,and no one questioned it, then shame on us.,,,,
If the wire color coming off of thier devices was green and yet that is where they tied thier internal neutral of the device to,shame on them,,,,,

 

[don_resqcapt19]

There was no white wire. The listing standard permitted them to use the EGC as a grounded conductor as long as the current was 1/2mA or less.

 

[jap]

So if they were within the listing, what caused the change to require us to install the neutral?
Did some Occ Sensors the current breach the 1/2 MA or less standard ?

 

[GoldDigger]

So if they were within the listing, what caused the change to require us to install the neutral?
Did some Occ Sensors the current breach the 1/2 MA or less standard ?

I suspect that there were two motives for the change (which is still in progress).
1. The idea of any deliberate current on the EGC, no matter how small, was repugnant, and the .5ma exception was only intended as a stopgap.
2. If you have several motion sensors on the same circuit and there is also GFCI protection, then enough .5ma devices will end up tripping the GFCI.

Once there is a big enough installed base of switch outlets with grounded conductor present, it will be possible to market devices that actually connect to that grounded conductor (either by wiring design or by the electrician installing it connecting the device's return wire to grounded instead of EGC.)
At some point (maybe already?) devices which return current to the EGC via the yoke or a green screw or wire will no longer be produced.