Insulating Electrical Tape Recommendations

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FaradayFF

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Greetings, All
I need to use an insulating tape for wrapping around a bolted connection. Are there any recommendations as far as vendor or type?
My application requires a durable insulation material that can also withstand temperature hot spots. I was considering either a high strength fiberglass tape or electrical putty tape, but have not used them prior. The max. voltage level is 250V.
Thank you,
EE
 
With all the modern termination devices such as "Polaris" don't often see taped connections. Most likely showing my age but for years we used varnish carmbric for bolted connections (with rubber or vinyl overlay) but it does have a 220°F temperature rating. Above that we used glass tape, good for 392°F.;
 
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We used to wrap split-bolts with a layer of what was called cambric, then a layer of rubber tape, then one of friction tape, the latter which got replaced with electrical tape. Nowadays, we just use electrical tape.
 
I used the 3M electrical insulation tape, over a few wraps of sticky side out 33. Then wrap with 33. The first layer of 33 keeps the insulation tape from sticking. The electrical insulation tape fills in uneven spots.
 
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FaradayFF said:
Greetings, All
I need to use an insulating tape for wrapping around a bolted connection. Are there any recommendations as far as vendor or type?
My application requires a durable insulation material that can also withstand temperature hot spots. I was considering either a high strength fiberglass tape or electrical putty tape, but have not used them prior. The max. voltage level is 250V.
Thank you,
EE
Click to expand...

The comments above probably tell you all you need but I am sure you can download the Scotch catalog and pick something out
 
You need to follow the procedures given by the tape manufacturer.


Also see American Electricians Handbook.

Only thing I would add is varnished cambric is the one tape you will have a hard time finding because few electricians actually use it. I keep a roll for customers who are picky. I use a file on sharp edges which is the procedure above 10 kV anyway. All the varnished cambric does is to prevent the rubber splicing tape (130C) from sticking to everything, and to protect it from sharp edges. Personally I just use 88 (upgrade from 33+) but I “back wrap it”...stretch and wrap it sticky side out. Then I cut pieces of Scotchfill and mold it into really deep valleys around lugs and bolts. The rest of the procedure is as per 3M. All this is acceptable based on the 3M training we did.

One customer likes F1 tape aka 3M silicone tape. There is a higher voltage use for it but they substitute for rubber tape. It does come off much easier but it is very fragile and splits easily.
 
Thanks everyone for replies. My concern is procuring robust tape that will work fine with a bolted connection. My understanding it is easier to insulate a brazed connection; it appears Scotch 88 tape is robust enough for my application.
 
Question - is heat shrink tubing more applicable in installations where heavier current is present and more robust insulation is required?
Thanks,
EE
 
What exactly do you mean by a 'more robust insulation'?

Your insulation must prevent current from flowing out of your conductors to any surrounding conductive material.

It must not chemically damage your splice.

It must mechanically survive the environment.

It must not degrade at your required operating temperature.

It must mechanically survive installation over your splice.

For example, if you need to splice inside a motor you need to deal with high temperatures (motors tend to operate hot) and it must survive vibration. The video in post #8 is a good approach, I've used it.

If you need to insulate over 'split bolt' connectors you need to be a bit careful about stretching the tape over the sharp edges of the split bolt, but otherwise following the video works fine.

Using a pre-insulated set screw connector for the splice is generally very robust, and also easy to do.

Large heat shrink can be a real pain in the tush, since you need to provide even heating to get good shrink.

'Cold shrink' is _very_ nice, very thick and sturdy, but quite expensive. You basically have a slit spiral plastic tube with a heavy rubber tube stretched over it. Pull out the spiral and the rubber collapses over whatever you need to insulate/protect.

Often the _mechanical_ issue with high current systems is not heating of the spice, but rather mechanical stresses encountered during short circuit events. Insulation is not the way to deal with this, but rather proper bracing of the splice after it is made and insulated.

-Jon
 
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