AC power strips (not conditioned)

[JW]

Hey folks,
This is obviously going to expose my naiveté.

I started opening up my power strips just to see what's inside. I have this big Furman balanced power unit upstream, so I don't want these to be doing any sort of conditioning, or surge protection, as the Furman is already doing that. And the power strips I've bought don't mention that they do any conditioning or surge protection.

I'm curious though. They all generally have some ceramic disc caps that have something to do with the led on the power strip, and also a film cap or two between the hot and neutral.

What do these do? Should I remove the film cap/s?

Just looking for clean sine wave distribution.

 

[shabtek]

:'( :'( :'(
call your insurance agent first

 

[abechap024]

Those caps should just be shorting high frequency noise to ground. Or maybe they are some sort of things that short when their are huge voltage spikes (lightning). it shouldnt hurt to carefully disconnect them.

 

[CJ]

could be a Movistor,

looks exactly like a ceramic cap only different,  ???

it will be thicker than a normal cap, and it will have the leads visible under the body,

so many power strips these days, they all have different stuff inside,

i have a cheap one that actually beeps when you overload it,

a pic would help if you have the means,

 

[JW]

Here's a couple pics.
Sorry they're so bad/blurry.

The Wima looking thing has the markings: .1k 250V GPF 25/085/21/C

The blue ceramic looking things (Movistors?) have the markings: ST4 K130

 

[JW]

The blue discs

 

[CJ]

looks like a 0.1 uf cap and a couple of MOV's,

MOV's due have a certain lifespan, and their voltage rating gradually goes down with time,

failure mode is usually an explosion followed by smoke and fire caused by hot metal,

so they are commonly installed inside a metal enclosure,

but they adjust for this by jacking up the voltage rting well above the line voltage,

 

[Andy Peters]

The blue discs are MOVs.
They have an interesting flaw, which is that they degrade every time they absorb a voltage spike.
And as they degrade, they get leaky, which can lead to all sorts of weirdness. For example, we had a hum in the PA system at one of the local clubs. We thought our grounding was good, everything was balanced, etc etc.

At FOH we had a couple of power strips that were plugged into the same AC circuit as the console and the insert/drive rack. One was mainly used to power a couple of LittleLites. For some unrelated reason we unplugged that power strip and the hum went away. It was an old power strip and the MOVs were shot.

-a

 

[PRR]

> expose my naiveté.

Please keep your pants on.

> I don't want these to be doing any sort of conditioning, or surge protection, as the Furman is already doing that.

If the Furman is perfect, the dinguses in the strips never do anything. So what is the harm?

The Furman is not perfect. And in surge reduction, as in a Maine winter, layers are the way to go. A whole-house supressor in the cellar fusebox, another at any sub-panel feeding either dirty (well-pump) or clean (studio) loads, the Furman, and why not a dime more at the farthest end of the line, where a supressor has the most impedance back to the big/bad world?

> They all generally have some ceramic disc

This is interesting.

The national fire code bans temporary wiring in permanent use. However it does allow surge supressors on computer systems. *Perhaps* these dinguses make the strips kosher for long-term use.

> Here's a couple pics.

I would ban those from a studio. The contacts are cheap-cheap-cheap. They work until the middle of the best take, and then go crackly. If teased-abused back into operation, eventually they develop "glowing contact", go red-hot inside, set the carpet on fire etc.

As CR says, there are better choices. In the "affordable" range, I like *metal* shells which take standard duplex wall-receptacles; and often remove the cheap junk and use the $6 outlets from the better hardware store or electrical contractor supply.

I'm mildly fond of Belkin 10-Outlet Surge Protector F9D1001-15-DP, sold at Home Depot. Sturdy enough. Takes standard duplexes (however H-D does not stock *good* duplexes for upgrading). Loong 15' cord can be nice or awkward. It was a real deal at $25; however the price has gone up to $35.

 

[CJ]

now if you ever get rich, you can get one of these guys>

http://www.pacificpower.com/English/Products/AMX-Series.aspx