adhesive tape as an insulator?

Hi,

I’ve always heard adhesive tape can’t be used as insulator, but I don’t get why : I measured with a tester the resistance of a thin film of adhesive tape, and his resistance it’s above 2 Megaohm.
Isn’t 2 Megaohm enough to insulate even a large voltage such as 220 Volt? (-> 1 mA as current)

its due to fire and flashover, I use it on occasion for low voltage stuff, but I am not going to trust some office tape on 220v

Kapton tape is used a lot in industry. That's adhesive, and it's tape.

AWOL: Kapton tape is used a lot in industry. That's adhesive, and it's tape.

Maybe it's insulator tape? I'm thinking of common office adhesive tape, not a specific one.

vams: Hi,

I've always heard adhesive tape can't be used as insulator, but I don't get why : I measured with a tester the resistance of a thin film of adhesive tape, and his resistance it's above 2 Megaohm. Isn't 2 Megaohm enough to insulate even a large voltage such as 220 Volt? (-> 1 mA as current)

It depends on what you are insulating. If you are insulating a semiconductor from a heatsink, you need the proper material to both insulate AND conduct heat to the heatsink.

For "ordinary wires", insulating tape of any kind will work, but you need to be concerned primarily with fire. If there is a short circuit, will the tape burn and cause a larger fire?

Will the tape dry out and crumble away in a year? How will the tape perform in warm, cold, dry or humid weather?

Sure, wrapping a few layers of plain clear tape over a wire will work, but it won't last long and it may be a fire hazard. Use the right stuff!

"common office adhesive tape" and 220V in the same breath. You have to be kidding.

First off, "common office adhesive tape" can mean anything or everything. Secondly, real electrical tape made for real insulation purposes costs a little over $1 a roll. Save a buck, burn the house down.

Read the specs - "excellent resistance to: abrasion, moisture, alkalies, acid, copper corrosion and varying weather conditions. It is a polyvinyl chloride (PVC) tape that is flame-retardant and conformable. 3M Temflex 1700 Tape provides excellent mechanical protection with minimum bulk. It is a UL Listed and CSA Certified “Insulating Tape. ... rated up to 600 volts".

http://www.jameco.com/1/1/9049-054007-69764-3m-temflex-vinyl-electrical-tape-1700-thickness-7-mils.html http://www.jameco.com/Jameco/Products/ProdDS/2153764.pdf

AWOL: Kapton tape is used a lot in industry. That's adhesive, and it's tape.

...and it's expensive - but still useful to have a roll for when you really, really need it (mainly for it's resistance to heat); btw - did you ever see the amount of kapton tape that NASA put on the Curiosity rover? There must've been a few hundred dollars worth of that tape on that machine (granted, that's a pittance compared to the cost of everything else)... :D

oric_dan: Read the specs - "excellent resistance to: abrasion, moisture, alkalies, acid, copper corrosion and varying weather conditions. It is a polyvinyl chloride (PVC) tape that is flame-retardant and conformable. 3M Temflex 1700 Tape provides excellent mechanical protection with minimum bulk. It is a UL Listed and CSA Certified “Insulating Tape. ... rated up to 600 volts".

I love 3M electrical tape - it's so much better than the generic stuff; very pliable, even in the cold. You may spend a little more on it per roll, but it's worth it!

Well thank you all for the answers, you made quite clear the subject.

Yes, adhesive tape acts as an insulator. That's why this tape is used for insulating electronic and electrical devices.

Scotch Tape type of clear adhesive tape also tends to generate large amounts of static charge quite easily. The triboelectric effect does not require friction, but merely coming into contact and pulling away again.

I had a single-board media player that I took out of its case and stuck to the back of a TV with a big piece of industrial velcro. It wouldn’t boot. I peeled the velcro off and put it back in its case and it worked fine. I don’t really know what to make of this, since it tended to be a finicky player anyway. Might’ve been something with the adhesive, or the substrate, or just the player being a PITA.

SirNickity:
I had a single-board media player that I took out of its case and stuck to the back of a TV with a big piece of industrial velcro. It wouldn’t boot. I peeled the velcro off and put it back in its case and it worked fine. I don’t really know what to make of this, since it tended to be a finicky player anyway. Might’ve been something with the adhesive, or the substrate, or just the player being a PITA.

Probably has something to do with noise emanating from the back of the TV.

// Per.

I think the point is that normal, old-school sticky tape is cellophane, which is cellulose rayon basically, a processed form of cellulose with much shorter polymer chains that can be dissolved in acetone and extruded and processed as fibres or ribbon/tape/sheet.

Cellulose absorbs a large quantity of moisture (a LOT) and thus becomes conducting in humid conditions and if splashed with water. Thus its unsuitable for electrical use (except low voltages in dry conditions). Its not very tough either.