Do you have a question? Post it now! No Registration Necessary
- Posted on
- Something Different
Re: Something Different
From the Wikipedia definition for dielectric breakdown:
"The maximum electric field strength that it can withstand intrinsically
without breaking down, i.e., without experiencing failure of its
IOW when it's insulating properties fail it becomes a CONDUCTOR.
From the Werner PDF file on fibreglass ladders for the electrical
industry, some tests on the CONDUCTIVITY of wood and fibreglass
2. DC leakage current(in uA) as related to conditioning for 10"
electrode spacing, 80% relative humidity conditioned at 22° C.
Time Wood Fiberglass Wood Fiberglass
As Received 90 KV 90 KV 7.0 1.0
24 hours 50 KV 90 KV 48.0 1.4
48 hours 50 KV 90 KV 67.0 1.9
72 hours 50 KV 90 KV 120.0 2.4
As you can see at 50KV wood begins to CONDUCT, now what part of this
concept don't you understand?. Are you aware that lightning is higher
in voltage than 50KV?.
Conduction at high voltage: rubber
I once made the mistake of trying to use once inch dia. black rubber
tubing to insulate some conductors with 47KV on them: after a few
seconds it begans to smoke heavily and start to pop: I assume the
rubber had carbon black added to colour it. The stuff was more of a
resistor than an insulator at those voltages.
Apparently hot glass is conductive from the sodium ions in it as well
: heat some up till it's red and then microwave it to see a lightshow.
Re: Conduction at high voltage: rubber
The wires were attached to the ends of the 60cm length of rubber tube
which was used to space the wires out as they were not rated for HV.
The voltage was able to breakdown the 1000V rated insulation and cause
enough flow across the rubber to make it start crackling and popping
with lots of smoke.