# Tape equivelant to insulation



## MWayne

Of of the other electricians went to some mandatory OSHA training last week and the person running the training, seeing his I&E shirt, asked him how many wraps of tape it takes to equal wire insulation. The electrician didn't know right off hand so OSHA person's answer was twenty wraps!? More of us I&E are going to this training next week and I want to have right answer if the question comes up again. Looking at 3M's PDF for 33 leads me to believe 2 half wraps are good for 600 VAC. Are OSHA standards different? Twenty wraps would be quite awkward most of the time.


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## Hackster

I thought it was 1 wrap?


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## Bbsound

Hackster said:


> I thought it was 1 wrap?


Me too


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## Zog

MWayne said:


> Of of the other electricians went to some mandatory OSHA training last week and the person running the training, seeing his I&E shirt, asked him how many wraps of tape it takes to equal wire insulation. The electrician didn't know right off hand so OSHA person's answer was twenty wraps!? More of us I&E are going to this training next week and I want to have right answer if the question comes up again. Looking at 3M's PDF for 33 leads me to believe 2 half wraps are good for 600 VAC. Are OSHA standards different? Twenty wraps would be quite awkward most of the time.


Wrap what? Why would OSHA have any input unless you are insulating tools.


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## BBQ

I always took the NEC section 110.14(B) regarding this to require the tape to be electrically and physically equivalent. 

So even when you have reached 600 volts you still need to be as thick as the original insulation. 


From 110.14(B)


> All splices and joints and the free ends of conductors shall be covered with an insulation equivalent to that of the conductors


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## BBQ

Zog said:


> Wrap what? Why would OSHA have any input unless you are insulating tools.


Repair of cords with tape, splices made on temp wiring are just two examples OSHA covers in their standards.


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## xaH

BBQ said:


> I always took the NEC section 110.14(B) regarding this to require the tape to be electrically and physically equivalent.
> 
> So even when you have reached 600 volts you still need to be as think as the original insulation.
> 
> 
> From 110.14(B)


So how many wraps would be required to repair a 5 KV cable? :laughing:


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## BBQ

Osha



> 1910.303(c)(3)(i)
> 
> conductors shall be spliced or joined with splicing devices identified for the use or by brazing, welding, or soldering with a fusible metal or alloy. Soldered splices shall first be spliced or joined to be mechanically and electrically secure without solder and then soldered. all splices and joints and the free ends of conductors shall be covered with an insulation equivalent to that of the conductors or with an insulating device identified for the purpose.


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## Hackster

I don't think I agree with the code requiring the tape to be physically as thick as the insulation. However, I agree that it's an odd situation because there is more than just voltage rating.


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## BBQ

Hackster said:


> I don't think I agree with the code requiring the tape to be physically as thick as the insulation. However, I agree that it's an odd situation because there is more than just voltage rating.


The really great thing is it does not matter at all what you and I think, it is up to the AHJ to determine what 'equivalent to' means.


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## Hackster

BBQ said:


> The really great thing is it does not matter at all what you and I think, it is up to the AHJ to determine what 'equivalent to' means.


You're right. Based off of that, I think we should stop all discussion about anything to do with code.


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## Big John

BBQ said:


> ...So even when you have reached 600 volts you still need to be as thick as the original insulation....


 I agree, but I still think the OSHA trainer was blowing smoke:

Looks like the nominal thickness for 14 or 12 THHN insulation is 0.4826mm (19 mils).

Super 33+ has a thickness of 0.178mm per wrap.

0.4826 / 0.178 = 2.71 or three wraps to achieve the same insulation thickness at triple the voltage rating.


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## BBQ

Big John said:


> I agree, but I still think the OSHA trainer was blowing smoke:
> 
> This lists the total thickness of 14 or 12 THHN insulation at 0.4826mm (19 mils).
> 
> Super 33+ has an thickness of 0.178mm per wrap.
> 
> 0.4826 / 0.178 = 2.71 or three wraps to achieve the same insulation thickness at triple the voltage rating.


No argument from me, 20 wraps would be a nuts.


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## BBQ

Hackster said:


> You're right. Based off of that, I think we should stop all discussion about anything to do with code.


Bye bye. :thumbsup:


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## MWayne

Thanks all, so it appears there is no real empirical justification for 20 wraps, only imaginary justification


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## sbrn33

1 wrap or twenty wraps. 600 volt tape is only good for 600 volt. At least that is what makes sense to me. Although I wouldn't trust 1 wrap of tape on 480 volt for my screwdriver. It gets at least three.


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## papaotis

something we might all be overlooking; how many wraps of TAPE is equivalant to the insulation? ask your osha guy THAT! very different materials sometimes


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## wendon

Three wraps of 33+ is good enough.


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## daveEM

Haven't done this for years and years but is there no more rubber tape? Used to throw a couple of wraps of that, then a couple of wraps of the 33.


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## FastFokker

When I wrap split bolts, I wrap the hell out of them... Probably 10 wraps of rubber tape and 10 wraps of electrical tape. One wrap of each might hold the voltage in, until it rubs against something.


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## glen1971

The way I was taught was the Scotch 130 (rubber tape) is for the insulation and the Super 88 (black vynl tape) is for the outer protection of the insulation...


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## tfo

glen1971 said:


> The way I was taught was the Scotch 130 (rubber tape) is for the insulation and the Super 88 (black vynl tape) is for the outer protection of the insulation...


This is also standard practice where i work.


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## Amish Electrician

What, pray tell, does "equivalent" mean? In take to mean, since we're talking about insulation, to mean 'equal in insulating ability.'

I'd like to hear the OSHA guy's substantiation of his understanding that 'equal' means 'equal thickness.'

FWIW, UL tests tape using two thicknesses of tape. Nor are the ratings cumulative. 600-V tape is good for 600 volts max, no matter how many layers you have.


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## MWayne

As a follow up:

The tape issue didn't come up and none of us were wanting to prolong the class by doing so but I did learn a couple of things. 
It is permissible to have a repaired extension cord 12AWG or larger. 
When resistance in a circuit goes up, so does amperage. 
When you are working in the heat you can sweat out from 2 pints up to a quart an hour. 

I would say please don't shoot the messenger but those kind of appeals fall on deaf ears here, so fire away!


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## Big John

Amish Electrician said:


> ...FWIW, UL tests tape using two thicknesses of tape. Nor are the ratings cumulative. 600-V tape is good for 600 volts max, no matter how many layers you have.


 Good point.

What I said earlier about three layers being "triple the voltage" is still my opinion, but it should definitely not be used like that.


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## mbednarik

BBQ said:


> Osha


Shouldn't we be looking in CFR 1926? 1910 is for general industry and 1926 is for construction.


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## mbednarik

MWayne said:


> As a follow up:
> 
> The tape issue didn't come up and none of us were wanting to prolong the class by doing so but I did learn a couple of things.
> It is permissible to have a repaired extension cord 12AWG or larger.
> When resistance in a circuit goes up, so does amperage.
> When you are working in the heat you can sweat out from 2 pints up to a quart an hour.
> 
> I would say please don't shoot the messenger but those kind of appeals fall on deaf ears here, so fire away!


I have heard some interesting things in OSHA training, but that is a 1st. resistance and amperage are inversely proportional. I also had an OSHA instructor tell me if a generator if not properly bonded, the OCPD would not work, which he is kinda right. If the neutral and EG are not bonded and it is being used as a stand alone generator, if a piece of equipment were to fault to ground it would just energize the EG of everything connected. He then told me he tied the hot to the neutral for testing purposes and the genset was producing 52 amps and was not tripping the OCPD because the grn to neutral bond was not in place.:blink: I told him OCPD does not care were the amperage is going, bonded or not, if it was a 30 amp breaker with 52 amps on it for a prolonged period of time, that there was something wrong with the breaker.:laughing:


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## Big John

MWayne said:


> ...It is permissible to have a repaired extension cord 12AWG or larger....


Contrary to popular belief you can repair an extension cord without it being an OSHA violation.


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## mbednarik

Maybe I am missing something, but that art just says that they can be field made with suitable parts = to that of a ul listed cord. I didn't see anything about tape or shrink tube repair.


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## wildleg

MWayne said:


> ..... doing so but I did learn a couple of things.
> ...
> When resistance in a circuit goes up, so does amperage.
> ...!


better send a telegram to mr OHM

http://www.physicsclassroom.com/class/circuits/u9l3c.cfm


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## jimmy21

i thought it was 600 volts per wrap?


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## uconduit

Never grab a cord by the tool!


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## Celtic

MWayne said:


> Of of the other electricians went to some mandatory OSHA training last week and the person running the training, seeing his I&E shirt, asked him how many wraps of tape it takes to equal wire insulation. The electrician didn't know right off hand so OSHA person's answer was twenty wraps!?


The followup to the OSHA guys answer should have been a question....

Is that 20 wraps for:
- blue painters tape
- "jap wrap"
- 33
- 88
- 130C
or a combination of the same?


...after he gives a ridiculous answer to that question, you hit him with insulation types:
- THHN
- XHHN
- XLPE

...after he gives a ridiculous answer to that question, you hit him with voltages:
- 120VAC
- 277 VAC
- 15KVAC
- 600VDC

:laughing:


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## papaotis

mbednarik said:


> Maybe I am missing something, but that art just says that they can be field made with suitable parts = to that of a ul listed cord. I didn't see anything about tape or shrink tube repair.


the osha class i went to just last fall didnt elaborate on the kinds of repairs, just that they were now allowed, and they werent before.:blink:


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