Electrical Question for the Shed

[D'Animal]

I have a 200amp service in shed. All electrical is ran in Conduit. The Ground rod for the electrical panel is a 8' brass/copper rod that is in the ground 6 1/2'. Everything workds as it should from the 8' T8 florescent light mounted to the ceiling, to the welders, to the air compressors, etc.

My problem is when I plug in any battery charger or turn on one set of florescent lights above my work bench. The Radios go all to static. Could there be a ground issue or some other little thing?

Thanks

 

[batcon]

I bet it's just am that's a problem, not fm on your radio.

 

[Capt. Jim]

It is interference from the ballast in the fluorescent light and the transformer in the charger. Most likely nothing wrong with your grounds. Sometimes they can even emit RF. So, you are either getting the interference through the common electrical wiring or the said devices are generating RF signals that the radio picks up. It tends to happen more with RF on the AM band and not so much on FM. Line driven interference can affect either band. Cheap light dimmers also do it. A cheap radio will be more susceptible to this interference.

 

[splitshot]

I agree with ^^^^^

And stop calling it a shed..

 

[toy4xfun]

Dan is this a sub panel, or a main service?

 

[D'Animal]

I had to upgrade the main service on the house to 400 amp. 200 goes to the house and 200amp service panel at the shed/shop.

 

[fj40charles]

Dan,

Any chance you the subpanel gound is bonded in your "shed."

Charles

 

[D'Animal]

Do you mean is it somehow wired/grounded to the building instead of just the grounding rod?

 

[fj40charles]

Do you mean is it somehow wired/grounded to the building instead of just the grounding rod?

Neutral and ground wire should NOT be connected together (bonded) in the subpanel.

 

[fj40charles]

Dan,

I have T8 fluorescent lights in my shop. I do not get any radio interference at all.
All my lights were purchased at Texas Fluorescents.
Home | Texas Fluorescents | Specification Products At Budget Prices

Interesting thread about RF noise when using cheap fluorescent lights. The problem is with cheap ballasts they put in these lights.
Lights, Radio interference - The Garage Journal Board

All of the wiring in my little shop is in EMT conduit and everything is properly grounded.

I'm guessing the close location of the bench lights to the radio is causing the radio noise.

Charles

 

[toy4xfun]

Dan being a sub panel the ground and neutral should go to your main service. and they should be isolated from each other all the way to the main service, if at any where they are not they can cause the problem you are having and worse, there is a possibility you can get a good shock.

pm lambcrusher, he is closer to you than me. and can look at it for you, also a ground rod should be 8' to 10' long and on new services there should be three, they should be in a triangle configuration at least 6' apart.

 

[LandCruiserPhil]

Edit-

Try connecting your net and ground. - Could be required depend on what year it was installed and what year NEC your city has adopted.
Also you may want to check your ground and see if you have 25 ohms or less at your sub panel. This is the minimum required by the NEC.
Make sure the case of the charger is properly grounded. If the transformer is rubber mount it could be missing an adequate case ground and still work.

 

[toy4xfun]

look i do this for a living, i know what they being the jurisdiction having authority, and MD, VA, DC, AND WV all require the ground that i said. not sure what they require out there, and he heavy up'ed his main to do his shop so your exceptions do not work here, but he is having a problem that sounds to me like he has to much emf on his grounds. so i was just trying to give him reasons why it could happen.

 

[LandCruiserPhil]

look i do this for a living, i know what they being the jurisdiction having authority, and MD, VA, DC, AND WV all require the ground that i said. not sure what they require out there, and he heavy up'ed his main to do his shop so your exceptions do not work here, but he is having a problem that sounds to me like he has to much emf on his grounds. so i was just trying to give him reasons why it could happen.

Sorry my intent was not to offend you. I will re-word my post

 

[toy4xfun]

i have to apologize i have been dealing with hot electrical problems today. and buy Hot i mean i was working on a energized panel, but some how i think you already know that.
so no beef with me i am good and no you did not have to say you were sorry.

 

[D'Animal]

I definately do not have three ground rods.

 

[fledglingme]

since you refered to the panel in the "shed" as a service panel, and that theres a gounding rod that's connected to said panel chances are very good that the neutral buss is being used as both neutral and gound connections. clearly if that's the case it is a code violation( i belive the NEC mandated this, like 20years ago-can't sware to the time) where or not this is the origin of you're noise problem remainds to be figured out

 

[LAMBCRUSHER]

Post a picture of the inside of your "sheds" panel. Turn off the breaker in your main feeding said "shed" first. My house is more of a "shed" than your gear grinders heaven BTW

 

[porten1134]

i doubt grounding is the issue, i do believe the light or charger may be to blame. most of the chargers are just a two wire cord (no ground) and most of the ballasts in lights just use the ground for a reference, and no real power is discharges through them.

the battery charger uses solid state components to change ac to dc. more than likely the light has an electronic ballast in it also. even if its a magnetic ballast, the lights and the charger will produce a non linear (sp?) load. meaning it doesent use the power in a nice smooth way, it will use short little bursts. this creates other frequencies in the wiring, on top of the normal 60hz in US wiring systems......harmonics. its a little unusual to see a problem manifest with just one or two components on the electrical system.most times you'll only start to see problems if there are a lot of lights or electronics, like in a large office or something. however, there might be other things creating non-linear loads on other circuits, or even on the service wires feeding the neighborhood.

a few things you could try:

plug the charger and light into another circuit

give every circuit its own neutral....dont share neutrals for branch circuits

over size the neutral wire....use a larger gauge of wire.

try a TVSS. ( a surge supressor), not just a little plug strip kinda thing, one wired into your sub panel. get one with a neutral conection, not just the "hot" wires.

just a thought. but without measuring the frequency there it seems like a pretty good guess.good luck!

 

[toy4xfun]

the first step before going through all of this is to check the original ground, i could go on and on with what problems a grounding issue can cause, also yes harmonics is most likely the factor here but are they out of control because of an improper grounding issue, if the grounded conductor and grounding conductor are combined in a sub panel than the normal harmonics produced buy these devices will cause the problem he is having.