Is a neutral required?

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jap said:
So who eventually figured out that they were using the EGC as the Neutral conductor when their device was attached to the wiring system?
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This is one of those things that has quietly snuck in under our noses over the last two decades.

The pressure to do it comes from Design and from Marketing as Corporate strives to keep or gain market share. All manner of switches can be made "marketable" by adding design features that include LEDs and little microprocessors that have to stay energized and working even when the switch is on. Putting a battery in was a possibility, but very few manufacturers chose to do that. The only way to get a good supply for the solid state features of the switch was to add a neutral (which many switch boxes in the real world don't have) or use the EGC.

Creative engineers, et. al., took advantage of the very low current needs of well designed solid state circuitry to exploit the listing standards allowance of a tiny amount of current "leakage" into the EGC.

Meanwhile, in the field, as we install there "smart" devices, just think of all the switches with a hot, a switched leg, and an EGC and no neutral that you've installed. Anything that keeps the circuitry alive while the hot is solidly connected to the switched hot (the switch is ON) has to be using the EGC as the "return" conductor for that circuitry.
 
They should have never manufactured a device that put any current on the equipment grounding conductors to begin with.

Those Turkeys,,,,,, all they had to do was ask us.
 
GoldDigger said:
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.
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I'm seeing the neutral on new smart devices more, but, from the switch manufacturer's perspective there's still gold in them thar hills of all the two wire switch loops in the existing housing stock of North America. UL has to evolve it's standards to exclude, or further limit, the current on the EGC for the manufacturers to really change.
 
what about an autotransformer?

what about an autotransformer?

iwire said:
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.
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would it be acceptable to size the conductors normally, accept some losses in the wire, and use
an autotransformer? That would be my first thought.
 
al hildenbrand said:
... UL has to evolve it's standards to exclude, or further limit, the current on the EGC for the manufacturers to really change.
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UL said that the standards would be changed if the NEC required the grounded conductor at light switch locations. Not sure if they have issued a new standard yet.
 
ryanpickett2003 said:
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.
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jap said:
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.
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I would have explored the option of wiring them all at 480 Volts. Much less voltage drop, and smaller wire required.

We did a ballfield with 78,000 watts of lighting all on 480 Volts. Even at 500+ feet away from the service, no larger wire sizes was needed with the higher voltage.
 
Right.....way high the loads are off, or partially off. But what if it was a single load?
 
jes25 said:
Right.....way high the loads are off, or partially off. But what if it was a single load?
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You would end up with a neutral in the formal sense, but not a grounded conductor.
As long as the 120 volt equipment did not require a grounded conductor, it would probably work. But if either phase failed, the 120 volt circuit would see close to zero volts and both sides of any connected device would be hot.
If you used an isolated secondary transformer instead of an autotransformer, you could treat it as an SDS and ground one side of the 120 locally (assuming that other code provisions allowed it.)
 
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GoldDigger said:
You would end up with a neutral in the formal sense, but not a grounded conductor.
As long as the 120 volt equipment did not require a grounded conductor, it would probably work. But if either phase failed, the 120 volt circuit would see close to zero volts and both sides of any connected device would be hot.
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I was thinking more along the lines if using the auto transformer to deal with the vd instead of the big wire. Not address the whole lack of neutral thing
 
jes25 said:
Your right. Just thinking. Thanks for the input
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Never use a buck/boost for voltage drop if there is more then one load, in the case of OP using an auto transformer to boost the voltage would end up providing over voltage to the controls when the light is turned off even if it was to one light fixture that had a photo cell, the photo cell would see the higher voltage when the light is switched off during the day.

As far as the OP the design of this system should have been a 480 volt service set out by the road, the NEC requires that if this is a grounded system then the grounded conductor must be brought to the first service disconnect(250.24(C), if not needed after that point it is not required but a EGC will be so you will still need a EGC run to the controls, If available from the utility a grounded delta would eliminate the need for a neutral but give very few options for other voltages later on except by using transformers which is still a cost effective method since you can just size them for the 120 volt loads if so needed.

The requirement for bringing the grounded conductor to the first service disconnect has been in the code for years, I think it was added in the 1999 but was 250.24(B) not sure if it was in the 1996 version, it was moved to 250.244(C) in 2005 and many didn't even know it was in the code until this move.

The reason is so there is a low impedance fault path to at least the service disconnect after such then the EGC is the fault path.

But with a corner grounded delta since you would most likely bring all the phase conductors to the equipment anyways you would bring the grounded conductor to the end controls.

Also some utilities offer a single phase highway lighting service @ 480 volts that might be used if available, although a 3-phase delta would offer a greater VD and the loads are distributed across all three phases and would have less load on any one conductor.
 
hurk27 said:
Never use a buck/boost for voltage drop if there is more then one load, in the case of OP using an auto transformer to boost the voltage would end up providing over voltage to the controls when the light is turned off even if it was to one light fixture that had a photo cell, the photo cell would see the higher voltage when the light is switched off during the day.
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I am not sure using a buck boost to overcome voltage drop for even one load would be NEC compliant.



As far as the OP the design of this system should have been a 480 volt service set out by the road,
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Absolutely. :)
 
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