ECN Forum Forums General Topics of the Trade General Discussion Area static electricity in outdoor deck

I have been asked to solve a static electricity problem & so far I haven't been able to find an acceptable solution. I've talked to 3 friends of mine who are also electricians and 3 electrical inspectors...no luck. If anyone has any suggestions it would be appreciated. The owners of a residential home spent big $$$ having a plastic composite plank deck installed on 3 levels of their home...none of the decks are at ground level. The planks are resting on 2x4 sleepers. Whenever they walk out onto any of the decks with their shoes on (rubber soled) they will get a static shock from the metal cap on the top of the wall / the door handle and even the bbq. I was on the deck with running shoes and got zapped multiple times. When I walked around in my socks only...no problem. I can't tell the owners to only go out on their new decks with barefeet or sock feet. The contractor who had the decking planks installed could not get any answers from the deck manifacturer. I'm wondering if I ground every plank, will the static charge discharge itself to ground instead of discharging through a person? Obviously the plastic planks don't conduct electricity but will the static electricity use this groundedpath?

Wireguy51:

WELCOME to ECN forums!

This is a great first post!!!

Gfretwell may be able to provide you with a idea.

I have heard that this is a big problem with composite decking. From what I have read, a grounding grid or other type of static drain wire doesn’t seem to help since the deck material itself is non conductive.
Some of the composite decking manufacturers claim that the static issue will subside as the decking ages, but it appears that in the meantime, their only answer to the problem is to either to avoid walking on the deck with bare feet, which seems ridiculous and unrealistic to me, especially in the summer months, or spraying the deck with water before use, which IMO, is equally ridiculous and impractical.

I have read that using an anti-static spray coating, something like the one in the link below can help, but it is not permanent and has to be reapplied every so often, so might get expensive after a while.

Staticide

If this was inside I would echo the static spray idea but you would still need a grounding grid for the static spray to bond to. I doubt the spray would last long outside.

The real answer is humidity but that is not something you have there I bet

We just got back from Colorado and it was pretty dry there too. I blew up the USB port on a laptop. (and I am supposed to know better)

I would note that the various deck materials differ radically in composition, and I suspect that the problem is confined to specific brands.

I imagine this is worst in the better brand (the ones that are 100% plastic). I bet the wood content of material like Trex would hold enough moisture to mitigate the static .. assuming you have some water in the air.

If they had access to them, use the anti-static shoe straps they use in ESD cleanrooms.

Another choice would be wearing a ball chain anklet with a trailing tail. Same concept as dragging chains under vehicles. However that could be a safety hazard if the wearer came in contact with a live wire or fixture.

Also driving a roofing nail thru the heel of the shoe and cutting it off flush with the bottom of the sole might work. Same hazard as the dragging chain.

Does anyone make a conductive stain or deck paint that looks good and is durable? Perhaps the conductive floor waxes we were not supposed to use on the insulating mats in the switchgear rooms.

How about somehow embedding carbon black or some other conductive material into the wood surface? Perhaps by a modified media blasting method.

Larry:

The decking in the OP is composite, not wood!

I wonder if a different type of shoe would help? Static is created from rubbing, AFAIK. Using a different composition shoe/sneaker/sandal or whatever may help.

Greg:
Going back in time, were there some types of shoes that were 'forbidden' before the birth of the anti-static floor wax on VCT.

HotLine1,

I realize the decking material is not wood. I mispoke when I typed wood. I should have stated deck surface.

Does anyone know what type of plastic is used in making the decking?

How much conductive material is mixed in with the resin when ESD dissapative containers are manufactured?

I am not sure what would be forbidden.
Until sometime in the 80s, you could smoke in a computer room. They certainly did not have a dress code.

We really did not think much about static until the mid 70s and one particularly ESD sensitive technology. The fix was to just bring up the humidity in the computer room. We did go around bonding the floor, clamping ferrite beads everywhere, spraying static suppressor and putting ESD mats under the consoles but when you got the RH up over 50% we didn't see the problems that often. When we did, it was actually just pointing out a real hardware problem. (Usually a poor ground connection on a "trilead", a small signal cable)
This was also when a lot of the urban legends got started.
They even went so far as to come up with an ESD generator to test the machines.

I stopped chasing ghosts pretty quickly, believing it was BS and just fixed the hardware problems!

The next generation of machine did away with trileads and all the static problems went away. That is also when IBM dropped a lot of the silly "requirements" they had come up with in the 70s like the IG receptacle.


To answer the OP, maybe just put a static mat in front of the door so you don't get zapped on the door knob