Electrical grounding for A/V cart

vonPoonBurGer

Ok, so I have a wire frame rack with plastic wheels, like this one, but much shorter. I use it to hold all the media center stuff that doesn't fit under my TV, including a home theater PC, an A/V receiver, an Xbox 360 and a VCR. I also live in Montreal, where the temperature has been a balmy -10C on average lately, and ambient humidity is an arid 25% or so. Needless to say, with the dryness I've noticed a lot of static electricity.

A few shocks now and then I can live with, but what I don't like is that I frequently end up shocking my metal-frame entertainment unit when I go to change games in the 360. Worse yet, it looks like that energy has nowhere to go except through my expensive and cherished electronics. At least, that's the conclusion I've drawn from the speaker crackling and image flickering that happens whenever I inadvertently shock that metal cart.

The apartment I live in is quite old, and has radiators, so there's no central forced-air humidifier here, nor the potential for one. I've already got a beefy console humidifier boosting the humidity in my apartment to 40%, which has reduced the amount of static, but not eliminated it. I don't think it would be feasible to keep ambient humidity much higher than that, so I'm curious to find out if there's a way to ground that cart.

Can anyone tell me if there's a way to ground that metal cart so that the static has a path to take that isn't through my electronics? Would running a wire from the cart to one of the radiators do the trick? Is there any way to use the third prong of grounded electrical outlets for this purpose, or is that a horribly bad idea? Despite my fetish for electronic gadgets, I'm actually pretty hopeless when it comes to understanding their inner workings or the nature of electricity, so any advice would be much appreciated.

DrFrylock

I am not an electrical engineer or an electrican and really don't know the answer to this.

When I work on electronics, I work with a grounding strap that is basically a metal patch that touches my skin (on a wristband) and is connected by a wire to a little O that slips around the grounding pin of a 3-prong plug. I presume that a similar strategy would work for you (since you've already got a number of grounded electronics on the cart anyway). You should be able to just run a wire to a little washer or something that slips around the grounding plug of one of your devices. As long as the metal is touching and the device is plugged in, you should just be able to use the house ground.

vonPoonBurGer

One of my concerns was that running some kind of wire to the grounding pin might be bad idea. I hadn't even thought about grounding straps, so that's a good point. If the electricity people feel it's Ok to wire themselves to the grounding prong via a wrist strap, then it's probably safe for my cart. I probably have some grounding straps lying around, if not the parts to roll my own. Thanks!

Zifnab

If you want to be really geeky about it, you can wire each piece of equipment to the cart (put a piece of wire under a screw that attaches to a metal part of the case), then get some 0 or 00 gauge wire and run that out to either your cold water faucet or a 6ft spike in the ground outside. That seems to be overkill for what you're doing, but that's the general idea. The one thing to watch out for with using that third prong is whether or not it's actually hooked up to anything. Many older buildings with older wiring don't have the three conductors (like my house), so the third prong either isn't hooked to anything or just gets grounded to the box.

cramsin

Most av equipment is on a 'floating ground'- there is only 2 prongs on the electrical plug. This is to avoid ground loops which can have an adverse effect on the analog signals- creating hums in the speakers. This means however that the cases of the equipment can be at a different voltage to the ground, creating a shock when you touch it. I don't particularily have the experience to recomend some method over another, but connecting the casing to a pipe or something shouldn't be life threatening, if you make sure you're connecting the case and not whats inside. (Don't touch the power cables. If you think theres something wrong with them get an electrician.)