don't be a lazy bugger, and ground it

from what I remember from class-

" Circuit breakers protect Equipment only GFI's save lives "

Go ahead and ground it.

It's not about being shocked from no ground. Grounding provides the safety to not be shocked.

If all the metal is grounded them if a hot wire (in particular 115v) were to touch the metal it will short and hopefully blow the fuse or trip the breaker.

Without a ground if the same wire were to touch a piece of metal it becomes hot and you get bit.

While a 115v shock will normally not be harmful, if it travels the wrong way and goes thru your heart, it can ruin your whole day.

Do yourself and anyone that may own the machine in the future a favor and ground it.

What are you guys doing to ground an EM that doesn't already have a ground, and has no braid? You going in there and running braid to all the rails, the coin door, etc? =|

It isn't a bad idea. If a coil wire comes loose and contacts the lockdown bar or side rail, there is no path to ground except you when you touch the game. Yeah, it probably is not going to happen, but I've seen some strange things inside games that I thought weren't likely. Every game manufactured in the last 30+ years has everything grounded, there is a reason for this.

The coin door and power switch are most likely grounded but double check. Ground the lockdown bar and rails and the shooter rod assembly.

As fflint_18 mentioned, hopefully a fuse will blow if there is a short. But even if it doesn't, you want the path to ground to be something other than you. Having the game grounded means you are much less likely to become part of the circuit.

Just run some wire to the spots you need to ground and attach. Use a compression connector and attach to a bolt. Make sure everything ties back to the ground that comes into the cabinet. Use your meter on continuity to check your work at the plug's ground pin.

Coin door is a bad spot.

Many EMs use 115v coils on them.

Older Williams EMs that turn the game on via the left flipper means 115v at the flipper only insulated from you by a piece of fish paper.

That should be another issue you should solve.

I put a main power switch on mine and got rid of the left flipper turn on.

That is the one thing that I didn't leave original for safety concerns.

If someone receives a shock from one of these machines I don't think it will be a case where "I touched it and got zapped" (As if one touches it with their finger and received a light, frightening fingertip jolt).

The player is all over the lockdown bar, often with a good deal of pressure making an excellent connection to Earth through their feet. The lockdown bar is usually grounded to the coin door through mounting bolts so there is the potential. Although there's no braid to the side rails, it's possible they too could become electrified through the lock down bar.

The coin door usually -does- have a ground connection to it. It's not necessary for something wrong to happen within the machine for someone to receive a 120v shocking potential. If, for example the grounding lug on the plug had been broken off and the +30 year old line cord has a crack or other damage to it then it's very possible the HOT side could touch the center ground conductor and the only path to Earth would definitely be through the players hands and feet.

A $2 new plug with grounding lug will drastically reduce the chance of a fatal shock. I don't think the chances of danger is great but the $2 plug can buy piece of mind.

Yeah, my Card trix didn't even have a power cord on it when I got it, that's why I was asking, lol.. I'm gonna have to put a longer cord on it, figured I would deal with this at the same time. It doesn't seem that the game had any grounding on it at all, the old wire (which was cut off) was only a 2-conductor cord, i.e. no ground. Guess I'll look at it closely and if I don't find an obvious place to ground it, I'll just run a wire under the bottom plate in the cabinet and attach it to coin door/lockbar mech and go from there.

All I know is the WMS EM I set up recently did not have the lockdown bar and side rails grounded through the coin door. The coin door was grounded as was the on off switch, but the coin door was isolated and its ground didn't carry through to the lockdown bar and sides. I grounded the lockdown bar, side rails, and shooter rod.

Clay suggests attaching the ground wire to teh metal frame of the transformer. Ive followed that advice on all my machines.

Jeff

That is a good practice to do.^^ GFCI
In addition to the previous mentioned on what should be grounded.
Only get a fatal shock once. Not your choice where you end up though -> or
We all diagnose a machine live ,best to ground the most potential places against the possibility of most common and by all means do not touch a live with on hand while holding/touching a ground.
Things go bad when that happens.

GFCI(1).jpg

What does this do, exactly?

Not trying to be prickish, but I think that is sort of the issue here. Does running a wire to the frame of one part in an EM help anything? If not, then why bother? What parts should be grounded?

I think we (this group) had roughly this discussion about 4 months ago.

http://pinside.com/pinball/forum/topic/electrocution-and-how-to-avoid-it

I'm still waiting to hear of my first pinball fatality. It has been ..... 1,343,452,156,309 days since our last serious accident.

It would be more productive to ground the coin door (as long as all switches are isolated), lockdown latch, rails and legs than to ground just the transformer.

Yep ^at least on Gottliebs thats an improvement that the OEM fell short and the best place to attach the gr.wire.

On the ones I have replaced from 2 prong to 3 prong power cords ,the coin door or the hinge there has a grounding wire from the factory and terminated at the transformer,but was never truly finished till a ground from the 3 prong would complete the loop after attaching the ground wire from the 3 prong cord.

Concrete can conduct enough current to provide a lethal ground path with voltages as low as 110 volts.
Everyone at one time or another has gotten shocked ,but if you feel indestructible why wear a seat belt ? may not get in an accident but who is fooling who,just not worth the chance.

Here is some good info -> http://www.tubelab.com/Safety.htm

Yes^ you can do that depending on the proximity of parts to be grounded sometimes easier to use the mounting points of the trans.
You can daisy chain the wires as you go along ,reducing the amount needed.
If you have automatic wire strippers you can strip the existing wire and tie into it with no cutting of the wire. (unless you have hard/cracked insulation)
Just twist and solder.

Instead of add-a-ball ,call it add-a-zap!

Wire_strippers_2.JPG Wire_strippers.JPG

Daisy chain is good.

I use a piece of bare copper with ground lugs that you can slide on the wire and tighten. Makes a nice finished look. I start it wherever the line cord terminates. Sometimes that at the transformer and sometimes at a terminal/solder block at the back of the playfield. I then run it in a loop all the way around the playfield grounding everythi8ng I can.

"Add a Zap" bad idea. With my luck someone will have a pace maker and I'll end up in jail.

Yes, folks have been shocked from pinball and just shrug it off.

Here's a scenario for you.

Friend working inside pinball box.

The hot from one of the line inputs had a rubbed bare/dry rotted spot that was touching the transformer.

Friend touches the ungrounded transformer casing.

Zap. Good shock. Jerks his body up and dislodges the bar holding up the playfield.

Playfield comes crashing down embedding either a slingshot relay or a Pop bumper relay assembly into his skull.

And gets knocked out.

When he comes too he's too shook up to get himself out of the predicament.

Wife finds him 30 min later (he didn't come up for dinner)

20 stitches later and a hairline fracture of his skull (must have a soft head) he was back at it.

Mind you he now built a safety of sorts so the playfield won't come crashing down.

And I helped him ground all the metal parts.

I just wish I had a camera on him. Would have gone viral on You Tube. "Man eaten by pinball machine"

This just goes to prove what a professor told me 25 years ago. "It's not always the shock that kills you, but the shock may start a chain reaction that will kill you" So don't get shocked!!

I tried one very similar to this as a kid.

Ye ha it will make your hair stand on end.

Are gottlieb EMs directly connected thru the coin door to other metal parts? Coin shoots don't touch the mechs. Williams EMs are, with at least two coindoor bolts going thru the lock bar receiver.

On the Jacks Open I'm working on (1977, end of the EMs), the 3 prong plug goes to the case on the transformer. From there, it branches out as the familiar green ground wire (with a yellow tracer) and goes to two places: The coin door and the metal frame on the on/off switch.

The way the door/lockdown/siderails are configured, the coin door ground would cover the side rails and via the lockdown bar, assuming good, tight, clean connections through the mechanical parts.

On a once routed EM I have, some one has run ground wire all around the inside of the cabinet. A green wire from the coin door, to connect with all of the leg brackets, back around to the ground wire on the tilt mech. It looks good, but I am sure it was not there when it left the factory.

On topic, and might be helpful to some... I have created a complete EM Pinball Grounding Kit, for anyone that needs to ground their Electromechanical Pinball Machines.

This kit comes with:
-16 AWG Grounding Wire with Terminals
-8 Quality Lock Washers
-4 Leg Bolt Nuts
-3 Zip Ties
-*14 Foot Black, 3 Prong Electrical Cord --> ** Available with the "Complete" Grounding Kit **

If you don't believe you need to ground the pinball legs, you can simply skip that step. Some feel it is overkill, but I feel I might as well do it while I am in there. ‍ The item is in my Pinside Shop and on my website TheEMScoreKeeper.com

I would at least do the front legs if you have little ones running around. They might grab onto the legs to support themselves.

IMG_1176 (resized).jpg

The worst pinball related shock I ever got was at a friend's house.
He had a Williams EM next to a DMD game. There was an AC leak on the EM, and I had one hand on the lockdown bar. I reached down to get my beer on the floor, and touched the grounded leg of the other game.
Wham! Pretty bad shock.
If the leg wasn't grounded, I wouldn't have gotten blasted, but I also wouldn't have known that the EM game had a hot wire in contact with (likely) the coin door.
A GFCI outlet would have tripped, and cut the power to the game plugged into it.