Wire Voltage Rating

[g1]

Terry, unfortunately I'm reading 300V on that pic of the Remington wire.

[big_teee]

Terry, unfortunately I'm reading 300V on that pic of the Remington wire.

I know!

Here's the email I just got from Larry.

"Hi,
The UL1007 rated wire is 300 volt and is so marked on the wire.
The UL1015 rated wire is 600 volt and is so marked on the wire.
Some of our pictures may be a representative image.

Larry "

Larry J.
Remington Industries

[Bill Moore]

Now I'm wondering, Terry! I used the cloth covered 20 ga wire on my last 2 builds, and CE says it is 600V rated in their specs, but I never even looked to see if there is anything on the insulation. (No problems though!)

[Enzo]

Fortunately, even if a wire is rated at 300v and you run 600v through it, that doesn;t mean it automatically arcs at 301 volts. Running the wire over rating is just bad practice, but not a guarantee of trouble.

[jmaf]

On guitar amps we run almost every single component above their rated maximum....Carling switches, tubes, check and you'll find some engineering abuse

[big_teee]

I know!
But, there is no reason to just try to F-up.
I'm still not comfortable running 450v in wire against a grounded chassis that says 300v on it, and only has .010" insulation.
You go ahead and do it if you like.
I have a choice, and I choose not to!
I'm ordering some 600v rated wire, for B+ use.
I can use the smaller .010" insulated wire for other things.
After all my grandson will more than likely be playing it.
That is incentive for me, to at least try to do things right!
Thanks Guys!
B_T

**I don't know Bill.
I don't use cloth wire on amps, not big into the vintage look.
I do use some cloth wire on pickups, and it has pvc over the wire, and cloth over the pvc.
I would think you have at least .030" total insulation, which is what 600v PVC wire has.

[Leo_Gnardo]

But, there is no reason to just try to F-up.
I'm still not comfortable running 450v in wire against a grounded chassis that says 300v on it, and only has .010" insulation.
You go ahead and do it if you like.
I have a choice, and I choose not to!
I'm ordering some 600v rated wire, for B+ use.
I can use the smaller .010" insulated wire for other things.
After all my grandson will more than likely be playing it.
That is incentive for me, to at least try to do things right!
Thanks Guys!
B_T

Good on you for ordering up some 600V rated.

I keep offcuts from transformer installs, that solves some small problems. Some are 1000V rated.

Also if there's a situation I'm not sure of, I'll slip on some clear heat shrink tubing. I use 3M polyolefin HST. I don't know what the voltage rating is, but take a w.a.g. that it's good for at least an extra 300-500V DC. Plus I like to shrink the heat shrink. Still magic after all these years, practically alchemy!



IT'S SHRINKING! SHRINKING I TELL YOU! WAH HA HA HAAAA!

[Enzo]

I wasn't cheerleading in favor of busting specs, just pointing out that one should not be surprised when the component works OK even over its spec.

[Steve A.]

I run my own tests on insulation using a cigarette lighter... if I don't like how it responds I don't use it.
BTW in another recent thread here regarding ampacity I learned that there are different ratings whether the wire is in open air or is bundled with other wires.

Steve Ahola

[Bill Moore]

I looked at some of my wire last night, nothing on the spool, and nothing on the jacket itself. It is the type with cloth over teflon, and therefore quite a lot of insulation. (If I still worked for the power company, I could check some with their meggar).
Are you heating the insulation Steve, and how do you determine it is OK?

[Steve A.]

I looked at some of my wire last night, nothing on the spool, and nothing on the jacket itself. It is the type with cloth over teflon, and therefore quite a lot of insulation. (If I still worked for the power company, I could check some with their meggar).
Are you heating the insulation Steve, and how do you determine it is OK?

"Flying by the seat of my pants?" I'll strip off some insulation, heat the bare wire end with a lighter and then observe what happens. Does the insulation bubble and get hard and crackly, or does it keep its shape and remain pliable?
It should be noted that I often buy crappy wire locally rather than buy the good stuff from the reputable online sellers.

Speaking of wire, I think that the decision whether to use solid or stranded is also important. I like solid wire for filament wiring where it can be twisted tightly and will stay right where you put it.

Steve

P.S. As for the cloth-covered pushback wire do any other industries use it these days? I would think that it would handle higher voltages, at least in regions without high humidity.

[nickb]

Here is a handy list of UL wire styles along with insulation thickness and voltage ratings.

I do wonder what the process is that comes up with these thicknesses given that the dielectric strength of PVC is about 725V per 0.001in. The UL1007 styles wires exceed this absolute limit by over 35x.

As an aside, I was working on a Sound City 120 today. The insulation is very thin on all the wires - certainly the thinnest I can recall in a tube amp - and it's still working after 40+ years. Not that I'm advocating using such wire

PS: I also remember a Marshall to which someone has added a pentode/triode switch. This was messily done with CAT5 twisted pair wire, good for 50V or so.

[loudthud]

It should be mentioned that a UL recognized product must have a HiPot test as part of the production process. With the power switch on, both sides of the mains are connected together and something like 3500V is applied for 1 minute. Leakage is measured at the end of the test. The exact details of the test depend on the type of product.

[jmaf]

Anyone know the voltage rating for wires in vintage Fender amps? I bet there are 50+ year old amplifiers out there using underrated wiring and which never had any issues.

[trobbins]

I recall 2 to 2.5kVAC applied for 1 minute, preceded and followed by an insulation resistance test at 500VDC, is a common routine test for industrial equipment. In a production environment with other QC controls, the high voltage is only applied for a second or two (to speed up testing). That testing can be a pain if you have specialist parts in your equipment, such as MOVs or caps from A/N to earth. If you were testing that 10kW audio amp's power supply on the bench then you may notice a bit of AC current flowing due to the increased stray capacitance of larger transformers