VOLTAGE for TEMPORARY LIGHTING

[CenDes]

Are there any code violations or concerns to using 277V for temporary lighting in a new high rise construction?

 

[BostonEE]

No, if the lighting is installed according to code it can be used temporarily or permanently. Is there something about the temporary installation that makes it unique?

 

[iwire]

Having a construction background I would advise against it.

Why?

1) if someone gets whacked by it the outcome is likely going to be worse.

2) The reason for using 277 is usally to install fewer circuits with more fixtures on each. This means when we have to shut it down to move or repair it we are putting more areas in the dark.

We use 120 volts with CFL lamps or 120 volt HID fixtures.

 

[iwire]

Is there something about the temporary installation that makes it unique?

I would say temporary construction wiring is unique and much more likely to be damaged while energized.

 

[CenDes]

There is nothing "unique" about the construction area or installation. Specifically the site is a new hospital facility in construction.

 

[qcroanoke]

Having a construction background I would advise against it.

Why?

1) if someone gets whacked by it the outcome is likely going to be worse.

2) The reason for using 277 is usally to install fewer circuits with more fixtures on each. This means when we have to shut it down to move or repair it we are putting more areas in the dark.

We use 120 volts with CFL lamps or 120 volt HID fixtures.

I have never seen a 480/277 temporary, but I have been out of the field for a long time.
And as Iwire said if you get hit by 277 it is really going to hurt........

 

[kwired]

We use 120 volts with CFL lamps or 120 volt HID fixtures.

Do you use them because you don't want to have 277 volt lighting for risk of exposure to 277 volts, or do you use them because 120 volts is almost always available at about any site?



Something else to consider is if it is temporary and part of a cord set with a cord cap - the 120 volt version will most likely be required to have GFCI protection on the receptacle. This will help with protecting people that encounter the cord or luminaires while working.

The 277 volt lighting will not have GFCI requirements whether cord and plug connected or not.



I do realize it says "Receptacles on construction sites shall not be installed on any branch circuit that supplies temporary lighting." in there.
I think that section needs more clarification, as a lot of cord and plug connected temporary lighting exists out there. Many of us have a cord and plug connected trouble light in our truck/van - isn't that a temporary light, and if so how can we ever use it without violating this section?

 

[iwire]

I would say temporary construction wiring is unique and much more likely to be damaged while energized.

There is nothing "unique" about the construction area or installation. Specifically the site is a new hospital facility in construction.

Temporary wiring in an area under construction is in fact unique when compared to permanent wiring methods.

Open splices (no enclosures) as allowed by the NEC.

Non-metallic cable wiring methods used in areas normally requiring metallic wiring methods

People moving large objects into tight areas, jamming the cables etc.


My experience tells me that the temporary wiring will be damaged a number of times over the period of construction.

We will distribute at 480Y/277, we will run feeders to specific equipment that requires 480 such as elevators and HVAC equipment but for general lighting circuits we will use 120 volts or 208 for some HIDs. To me it just makes good sense.

But to answer your question I do not know of any code rule preventing the use of 277 for lighting.

 

[iwire]

I have never seen a 480/277 temporary, but I have been out of the field for a long time.

If the building we are working on will have a 480Y/277 service we will have a 480Y/277 temp service for it. You end up needing it to power building systems as I mentioned above.

We have a number of temp transformers with panelboards mounted to them that we will place around the projects to provide the power. Sometimes even the temp trailers will get a 480 volt feeder to them that we step down right at the trailer.

 

[iwire]

Do you use them because you don't want to have 277 volt lighting for risk of exposure to 277 volts, or do you use them because 120 volts is almost always available at about any site?

As far as I know we don't have a written policy for temp lighting voltage, I just know how I handled it and how I the other foremen handle it.

I have seen enough damaged 120 volt temp wiring damaged by metal studs, metal duct work, sprinkler pipes, Sheetrock jamming the cables to metal structures that 277 scares me. People do occasionally get a shock from temp wiring no mater how much care is used to install it.

The CFL lamps do reduce the load but mostly we find they are much more tolerant to rough service than the incandescent lamps. (Besides, can you still get 100 A19s?)

Something else to consider is if it is temporary and part of a cord set with a cord cap - the 120 volt version will most likely be required to have GFCI protection on the receptacle. This will help with protecting people that encounter the cord or luminaires while working.

The 277 volt lighting will not have GFCI requirements whether cord and plug connected or not.



I do realize it says "Receptacles on construction sites shall not be installed on any branch circuit that supplies temporary lighting." in there.
I think that section needs more clarification, as a lot of cord and plug connected temporary lighting exists out there. Many of us have a cord and plug connected trouble light in our truck/van - isn't that a temporary light, and if so how can we ever use it without violating this section?

"Receptacles on construction sites shall not be installed on any branch circuit that supplies fastened in place temporary lighting."

I think we all know what they mean but wording it gets tricky, you might bring in a clamp on light and that gets fastened in place.

 

[GoldDigger]

It probably should have specified hard wired temp lighting instead.

Tapatalk!

 

[ActionDave]

I agree with Iwire on this one completely. Using 277V for temp. lighting is a bad idea even if it is allowable.

120V can be lethal of course, but 277V is one giant step further into the danger zone.

This plus the fact that construction sites are populated by a particular type of humans known as construction workers, a talented and hardworking bunch overall but a large portion of whom are a self contained natural disasters waiting to strike, add up to the choice of 277V for temp lighting being one of the worst someone could make.

 

[kwired]

Temporary wiring goes beyond just construction purposes. If 277 volt lighting is practical and will be in an area not subjected to whatever activity is going on it may become more reasonable to choose it over 120 volt lighting.

I do agree most general construction sites is probably wise to stick to 120 volts and maybe even GFCI where it is not otherwise required in some instances.