Article 590 Temp Power

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Isaiah

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590.4(C) allows hard usage and extra hard cable/cord to be laid directly on the floor as long as its protected from damage. Would this same scenario apply to a cable being directly laid on the earth, outdoors as long as its adequately protected?
 
I don't see that in 2020, but generally Yes, conductors may be laid on the ground. Adequate protecting might mean cable ramps across a drivewy or laying them along a fence line where it's really likely a vehicle might dive.
 
I see no allowance to lay any wiring method on the floor or ground, I looked at the 2020, 2017 and 2014. However I have never done any temporary wiring so I may be missing something here.
So lets start with the allowance to lay SO on the floor and were is that (per the OP)?
 
tom baker said:
I see no allowance to lay any wiring method on the floor or ground, I looked at the 2020, 2017 and 2014. However I have never done any temporary wiring so I may be missing something here.
So lets start with the allowance to lay SO on the floor and were is that (per the OP)?
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Look at 590.4(C)(1) it allows Branch Circuits of certain types of cables i.e. SE to be used “without concealment within walls, floors or ceilings.”


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Within walls, floors or ceilings is not the same as being laid on the floor or ground.
Perhaps tomorrow some one who has done temp wiring can help out. I have done temp wiring for events with SO cord to spiders laid on the pavement
 
tom baker said:
Perhaps tomorrow some one who has done temp wiring can help out. I have done temp wiring for events with SO cord to spiders laid on the pavement
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I can do that tonight :D.

It's extremely common to lay hard-service cord across, well, almost any solid surface. We use YellowJackets when crossing driveways and the like, and try to stick to existing barriers (fence, wall, etc) and stay out of walking paths. Over grass, gravel, asphalt, sand- no one has ever questioned the placement.

I think this is more of a case that the NEC doesn't prohibit the practice so it's allowed. I also think that 590.3 and .4 in the 2020 edition are poorly written (and some of the others aren't much better).

BTW, 2011 and 2014 don't have a 590.4(C)(1); 2020 does but it's not relevant. This really looks like 590.4(H) territory (Protection from accidental damage).
 
zbang said:
I can do that tonight :D.

It's extremely common to lay hard-service cord across, well, almost any solid surface. We use YellowJackets when crossing driveways and the like, and try to stick to existing barriers (fence, wall, etc) and stay out of walking paths. Over grass, gravel, asphalt, sand- no one has ever questioned the placement.

I think this is more of a case that the NEC doesn't prohibit the practice so it's allowed. I also think that 590.3 and .4 in the 2020 edition are poorly written (and some of the others aren't much better).

BTW, 2011 and 2014 don't have a 590.4(C)(1); 2020 does but it's not relevant. This really looks like 590.4(H) territory (Protection from accidental damage).
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Have you seen anywhere in the NEC that limits the length of the feeder laid on the ground? I didn't see any stipulations regarding this. Also, I didn't see any limitations on the voltage level nor number of phases.

Regards,
EE
 
No limits in Art. 590 although the general directions on voltage drop or nominal voltage ought to be observed. And if you need to run 1000's of feet, I'd seriously consider whether that's rational at all. For most of what I do, anything over maybe 500' will probably merit a generator instead (somewhat based on actual load and cable size).

There a lot of "it depends" here, can you give us more specifics of the project?
 
zbang said:
No limits in Art. 590 although the general directions on voltage drop or nominal voltage ought to be observed. And if you need to run 1000's of feet, I'd seriously consider whether that's rational at all. For most of what I do, anything over maybe 500' will probably merit a generator instead (somewhat based on actual load and cable size).

There a lot of "it depends" here, can you give us more specifics of the project?
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I'm looking at running 208V, 3 phase feeder a distance of about 250 feet. It would be connected using cam-locks on both ends.
Thanks,
EE
 
I instructed a 2014 code update class for a local navy shipyard, they used to lay SO cord on the bottom of the drydocks, all the disconnects were on temp supports. The change in the 2014 to disallow SO cord on floors caused a lot of wailing and gnashing of teeth.
 
tom baker said:
I see no allowance to lay any wiring method on the floor or ground, I looked at the 2020, 2017 and 2014. However I have never done any temporary wiring so I may be missing something here.
So lets start with the allowance to lay SO on the floor and were is that (per the OP)?
Click to expand...
What, no fairs!
 
Greentagger said:
Is 590.4(J) what you’re looking for?
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AHA...It does state that "cable assemblies and flexible cords and cables installed as branch circuits or feeders shall not be installed on the floor or on the ground".

However, it does state that "Extension cords shall not be required to comply with 590.4(J)".
I guess depending on how the system is configured, one could use the extension cord exception in this case.
 
250' of 208v? No problem at all unless you're into thousands of amps, then it's just a lot of copper.

What does "not installed on the floor" really mean? Not stapled to the floor? I know it's quite common practice to lay the feeders on the floor/ground, but they're usually SC cable., which is, well, designed for the purpose. There's a lot of "it depends" on what' happening at the site.

If everything is camlock, that sounds like an extension cord....... And if you flip over to 525, along the ground is allowed (252.20).

I still say 590 is a mess.
 
zbang said:
250' of 208v? No problem at all unless you're into thousands of amps, then it's just a lot of copper.

What does "not installed on the floor" really mean? Not stapled to the floor? I know it's quite common practice to lay the feeders on the floor/ground, but they're usually SC cable., which is, well, designed for the purpose. There's a lot of "it depends" on what' happening at the site.

If everything is camlock, that sounds like an extension cord....... And if you flip over to 525, along the ground is allowed (252.20).

I still say 590 is a mess.
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Agreed, I have seen "portable" cable laid on the ground, just shorterer run. I guess it should be fine, as long as it is proper insulation.
 
zbang said:
If everything is camlock, that sounds like an extension cord.......
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Started looking around NEC for a definition of "extension cord"...

According to 240.5(3) and 240.5(4) could the above statement be true? BTW, I'm just trying to understand the terminology, because I am very familiar with this being common practice.
 
zbang said:
Maybe... neither (3) or (4) would apply to a 200 amp set of leads used as a feeder; I'd go back to 240.5(A)- a common type SC spec says "NEC Table 400-5(B) for 90 °C (UL)".
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Gotcha. But if it's not an "extension cord" you can not use the "Extension Cord" exception as all other "cable assemblies and flexible cords and cables installed as branch circuits or feeders shall not be installed on the floor or on the ground". Without a definition of an extension cord it appears that a lot of people may not be following NEC.

Looking at 240.5(3) and 240.5(4) its implying that "extension cords" are either listed (which it appears that UL does have a listing for extension cords), or not be loaded with current greater than 20A, since it would have to be protected by a 20A OCPD.

Sorry since I'm not on the road I appear to have too much time on my hands.
 
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