Extension Cord Series (Prohibition)

[bestsafety]

I recently had a SAFETY discusion with a construction contractor regarding the "best-practice" of NOT connecting extension cords in a series. (That's been my practice for years!)

He says "Show me!" In NEC Code, MIOSHA, OSHA, Cal-OSHA, or ?????


My comments:

Manufacturer's tags often say it. (UL?)

There can be voltage drops.

Required GFCI's may not work properly.

Gauge of wire set for actual length of cord - may overheat.

I say for a "200 ft run use 200' cord, not 100' + 50' and 2-25'-ers!"

Any helpful references out there?

Thanks,
Bes

 

[jeff43222]

Re: Extension Cord Series (Prohibition)

You don't need any references. This guy doesn't understand that there's more to being an electrician than mastery of codebooks.

The exam I took had plenty of stuff on it that was not code-related. Voltage drop is not regulated by the NEC (they *recommend* limits, but that's it), but I sure had to know how to calculate it on the exam. Using his logic, eating buckets of dirt must be safe since there's no law against it.

All of the reasons you listed are valid. If your contractor acquaintance were an electrician, he would know this.

 

[69boss302]

Re: Extension Cord Series (Prohibition)

Sorry I can't give any direct references, but I have seen a couple guys burn up their power tools because of the voltage drop. They didn't even notice until the smoke was coming out because they didn't feel the heat because they were at least smart enough to wear gloves. Also couldn't get one contractor to understand why his portable air compressor wouldn't run when he had just about the same set up you mentioned. Try to tell them to look at the cords themselves. The longer cords use the larger wires to compensate for voltage drop. Shorter cord, smaller wire.

 

[jimwalker]

Re: Extension Cord Series (Prohibition)

Good luck at teaching him.Let him burn up his own tools.I have seen things like 100 ft#12 then 3 way splitter,then 100 more feet then 5 way splitter then some 50 and 100 ft cords.Why it works is beyond me.Just pure dumb luck that everything not running at same time.

 

[bestsafety]

Re: Extension Cord Series (Prohibition)

Thanks for the responses.

This is on a major industrial construction project and he wants to know how I can make him comply without a code compliance requirement. (New cords cost HIM money!?)

We don't have any "best practices" special safety conditions dealing with cords.

PS: - This a BIG contract for a major client, but the "lawyers" want to see it "in print" (in the contract).

 

[jeff43222]

Re: Extension Cord Series (Prohibition)

You really can't make this guy comply. All you can do is make sure your advice is noted for the record. If he chooses to ignore it, that's his problem.

Some people insist on learning things the hard way.

 

[69boss302]

Re: Extension Cord Series (Prohibition)

1910.305(g)(2)(ii)

Flexible cords shall be used only in continuous lengths without splice or tap. Hard service flexible cords No. 12 or larger may be repaired if spliced so that the splice retains the insulation, outer sheath properties, and usage characteristics of the cord being spliced.

This is out of the OSHA Standards and if you consider attaching another cord a tap (which I would say that is what it is) then this would prohibit such a thing.

 

[don_resqcapt19]

Re: Extension Cord Series (Prohibition)

Why would the GFCIs not work? How is one 200' cord that is hard to handle safer then cords of the same gauge connected together to make up the required length? The load and the cord wire gauge determines the voltage drop. A 200' #12 cord will have the same voltage drop and produce the same amount of heat as 4 50' #12 cords connected together if they both feed the same load.
Don

 

[jeff43222]

Re: Extension Cord Series (Prohibition)

I think the GFCIs might not work if they are connected downstream from where the extension cords are daisy-chained together. Perhaps if one of the cords isn't connected properly, it could result in a ground fault that the GFCI wouldn't trip on because the fault would be on the line side rather than the load side.

Portable GFCIs I use say right on the device that they are not supposed to be plugged into extension cords on the line side (i.e., they are supposed to be as far upstream as possible), but Mr. Cheapie Contractor sounds like the kind of guy who wouldn't pay any attention to that since it's not spelled out in a code book.

[ August 16, 2004, 05:01 PM: Message edited by: jeff43222 ]

 

[69boss302]

Re: Extension Cord Series (Prohibition)

I don't think you'll find a 200' cord made by a manufactured with #12. Now someone may do it in his own workshop. Most one's that I have bought once you go over 100' jump up to #10 and I've seen 200' s with #8.

 

[iwire]

Re: Extension Cord Series (Prohibition)

Bestsafety I work on very large jobs all the time and I would also tell you to show me a code that prohibits daisy chaining cords.

As it happens the company I work for only buys 100' 12 AWG cords but we still end up putting them together sometimes.

Voltage drop can be a problem for some trades like the metal stud guys chop-saw and the sprinkler fitters threading machine, if these guys are smart they have 10 AWG cords, if not it's their problem.

The Sheet rockers screw-guns on the other hand work great on 200' + of 14 AWG

As far as the GFCI protection the EC providing the temps should be handling that at the outlets (my preferred method) or at the breakers.

One 200' cord or four 50' cords will affect the GFCI protection in the same way. The longer the circuit length from the GFCI the more likely it will trip.