Do I need a ground pin?

[Hutchins Auto Repair]

Backyard shed wired up like this:
10-2 w ground hooked to my main panel in house on 30 amp breaker, ran to shed and landed in a new breaker box just so it would be easy to isolate the lights and outlets on separate circuits. Hot wire lands on the hot bar for the breakers, neutral and ground to the common buss bar. Shed outlets hot wire lands on 20 amp breaker and lights land on 15 amp breaker, with all neutrals and grounds landing on same common buss bar. Now, does this need a ground pin at the shed? I have two 8 foot T-8 fixtures in the shed and everything works fine except that when I turn on the flourescent lights, it kills my FM radio reception. Awful noise. Lights out, no problem. Also, no noise at all no matter what I run off the outlets. Only the lights ruin my radio, even if it is running off the batteries and not plugged in. I read the posts about this problem and concluded that it is the fault of the T-8 lights in conjunction with a metal building, but I was wondering if a ground pin might help. Also, is a ground pin necessary or required anyway? I am willing to go to T-12 lights instead, because I know they won't cause interference, but someone wrote that they will no longer make them in a year or so, is this right? Maybe I will just get ticked-off and put in regular screw in bulb fixtures! I think it's just the junky Lowes chinese lights, but I would like your input. Thanks in advance.

 

[MrMark]

This setup is definitely not right. You need a lot of help here - it's not safe. The ground pin is the least of your problems. You never connect the neutral to ground like you did. That happens only at the service entrance. You have other issues too. The pin is probably required for lightning.

 

[nehog]

Backyard shed wired up like this:
10-2 w ground hooked to my main panel in house on 30 amp breaker, ran to shed and landed in a new breaker box just so it would be easy to isolate the lights and outlets on separate circuits. Hot wire lands on the hot bar for the breakers, neutral and ground to the common buss bar. Shed outlets hot wire lands on 20 amp breaker and lights land on 15 amp breaker, with all neutrals and grounds landing on same common buss bar. Now, does this need a ground pin at the shed? I have two 8 foot T-8 fixtures in the shed and everything works fine except that when I turn on the flourescent lights, it kills my FM radio reception. Awful noise. Lights out, no problem. Also, no noise at all no matter what I run off the outlets. Only the lights ruin my radio, even if it is running off the batteries and not plugged in. I read the posts about this problem and concluded that it is the fault of the T-8 lights in conjunction with a metal building, but I was wondering if a ground pin might help. Also, is a ground pin necessary or required anyway? I am willing to go to T-12 lights instead, because I know they won't cause interference, but someone wrote that they will no longer make them in a year or so, is this right? Maybe I will just get ticked-off and put in regular screw in bulb fixtures! I think it's just the junky Lowes chinese lights, but I would like your input. Thanks in advance.

Pin? Talking about a ground rod? If so, there are specific rules on those and tons of threads in this forum about doing it.

Neutral should go to a neutral buss, and ground should go to a ground buss, not a combined buss for both...

 

[ishiboo]

Pin? Talking about a ground rod? If so, there are specific rules on those and tons of threads in this forum about doing it.

Neutral should go to a neutral buss, and ground should go to a ground buss, not a combined buss for both...

Given the limited scope of a "shed" I would not be too worried about the ground/neutrals sharing a bus, nor the absence of a grounding rod. I'm not sure based on 10-2 and the description if it's being used to supply 240, or just one single 120v/30A circuit. If there is only one leg to the shed, I'd use the neutral and ground properly and add the bus bar, especially since you have only two circuits to deal with and the wire is already there

The grounding rod would not solve your RFI issue though, you probably need to buy quality fluorescent lights. Are these older fixtures with magnetic ballasts? If so, you have no hope until you replace them.

 

[theoldwizard1]

Neutral should go to a neutral buss, and ground should go to a ground buss, not a combined buss for both...

At one time (20, 30, 50 ?) years ago, this was the norm.

Adding a ground rod and a separate ground in the box and for all outlets will not solve your problem. Get new electronic ballasts. Probably cheaper to just get new fixtures.

 

[ishiboo]

Given the limited scope of a "shed" I would not be too worried about the ground/neutrals sharing a bus, nor the absence of a grounding rod. I'm not sure based on 10-2 and the description if it's being used to supply 240, or just one single 120v/30A circuit. If there is only one leg to the shed, I'd use the neutral and ground properly and add the bus bar, especially since you have only two circuits to deal with and the wire is already there

The grounding rod would not solve your RFI issue though, you probably need to buy quality fluorescent lights. Are these older fixtures with magnetic ballasts? If so, you have no hope until you replace them.

Sorry, you have "outlets" so clearly it's 120 and not a neutral-less 240. Ignore that

 

[pattenp]

The best thing to do is to add a ground bar to your breaker box in the shed and connect your grounds to that bar. The ground bar needs to be bonded to the box. The existing neutral bar should have a ground bonding screw that needs to be removed to isolate the neutral bar from the box. Use the unbounded neutral bar for landing only the neutrals to. Get two grounding rods and drive them in the ground at least 6 feet apart from each other and run at least a #10 solid copper wire from your ground bar in the shed box to these rods. This is not to solve your RF problems it's just to make the install safer.

 

[nehog]

At one time (20, 30, 50 ?) years ago, this was the norm.

...

Certainly was the norm when my house (about 25 years old) was wired... One massive, combined neutral/ground buss bar. Hate it, and when I re-panel, I sure will make it 'right'...

 

[theoldwizard1]

The best thing to do is to add a ground bar to your breaker box in the shed and connect your grounds to that bar.

That won't solve his static problem.

 

[chopperimpala]

Certainly was the norm when my house (about 25 years old) was wired... One massive, combined neutral/ground buss bar.

So why is this (--NOT-- BEING A SMART ***!! A GENUINE QUESTION) not O.K. anymore? What has changed to deem this practice unsafe? I am asking because my house, built in 1977 is wired that way and when the shop was wired they ran the 2 hots, and also a neutral wire & ground wire COMBINED at the same buss bar in the house box, out side to the shop. In the shop box are the 2 hots, and then a neutral buss bar, and a seperate ground buss bar, bonded to the box, and then "daisy chained" out to the 2 ground posts in the ground.
thanks, Ken

 

[MrMark]

Because an open neutral will cause the ground wires to be unexpectedly energized.

 

[nehog]

OK, to try to drift back to the OPs question/problem.

I'd suggest adding a ground wire to the fixture to a dedicated ground, that may help. (this is separate from the green ground that already is there.) That MAY help, and may not.

What may be the best solution is to have an external antenna on the building. That moves the antenna away from the noise source, and increases the signal to noise ratio as well.

 

[Hutchins Auto Repair]

fixtures are brand new from lowes.
I am looking into my main panel to my house in my basement. Sure there is a separate buss bar for the neutrals and a separate one for the grounds, but there is a connector bar that bridges across the 2, hooking them all together, that the main service neutral bolts to. This strap/bar is also grounded to the box itself. How is this any different than the neutrals & grounds together on the same strip in the small shed breaker panel? The breaker panel is a siemans and there is only 1 buss bar in it! Thanks again for any help, all answers are very appreciated!

Also, my house was built in 1995. Never seen anything different than the way my house panel is set up.

 

[Gooch]

fixtures are brand new from lowes.
I am looking into my main panel to my house in my basement. Sure there is a separate buss bar for the neutrals and a separate one for the grounds, but there is a connector bar that bridges across the 2, hooking them all together, that the main service neutral bolts to. This strap/bar is also grounded to the box itself. How is this any different than the neutrals & grounds together on the same strip in the small shed breaker panel? The breaker panel is a siemans and there is only 1 buss bar in it! Thanks again for any help, all answers are very appreciated!

Also, my house was built in 1995. Never seen anything different than the way my house panel is set up.

It's required to be bonded at the first service disconnect means, it ensures that if there is a fault current to ground, it has a low impedance path back to the source. anything after that creats parallel paths for current to flow and can cause a difference of potential between the two panels grounds.

 

[pattenp]

Did you read my entire post? I said it would not solve his RF problem.

That won't solve his static problem.

 

[Hutchins Auto Repair]

Also, my house was built in 1995. Never seen anything different than the way my house panel is set up.


Oh I think I get what mrmark is saying, now that I thought about it enough, IF the neutral FEED that is coming into the shed panel became open, then the grounds all on that strip that go to everything in the shed could become energized. right? SO if it was on separate buss bars, and the neutral became open, it would just be a dead circuit, right? If this is the case then the breaker box in the SHED, should NOT have the neutral bar and ground bar connected at all, unlike the house main breaker box does, right? If this is so, then what does the ground wires eventually hook to? If the buss bar for the grounds is not hooked to anything that runs back to the main house? Do they instead connect to the grounding rod? Thanks again.

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Ah I see now that gooch has a reply that states this very thing. Thanks again. It seems that the way to go is to add a ground buss bar connected directly to the box and remove the bonding strap to the neutral isolated buss bar, and then connect the bare grounds buss bar to the grounding rods/pins. Thanks to all, never tried to hook up external shed before! Much better understanding now thanks to all you guys, and MrMark and Gooch. And special thanks to pattenp!

 

[MrMark]

fixtures are brand new from lowes.
I am looking into my main panel to my house in my basement. Sure there is a separate buss bar for the neutrals and a separate one for the grounds, but there is a connector bar that bridges across the 2, hooking them all together, that the main service neutral bolts to. This strap/bar is also grounded to the box itself. How is this any different than the neutrals & grounds together on the same strip in the small shed breaker panel? The breaker panel is a siemans and there is only 1 buss bar in it! Thanks again for any help, all answers are very appreciated!

Also, my house was built in 1995. Never seen anything different than the way my house panel is set up.


Oh I think I get what mrmark is saying, now that I thought about it enough, IF the neutral FEED that is coming into the shed panel became open, then the grounds all on that strip that go to everything in the shed could become energized. right? SO if it was on separate buss bars, and the neutral became open, it would just be a dead circuit, right? If this is the case then the breaker box in the SHED, should NOT have the neutral bar and ground bar connected at all, unlike the house main breaker box does, right? If this is so, then what does the ground wires eventually hook to? If the buss bar for the grounds is not hooked to anything that runs back to the main house? Do they instead connect to the grounding rod? Thanks again.

You are really close. Without N/G bonding at the shed, if the neutral becomes open circuit at the shed, your 120V power will be open circuit and nothing will flow. However, if you have N/G bonding at the shed and the neutral goes open then the circuit can complete through the ground wires (and anything metalic they touch) back to the service panel in your basement and then back to the utility through your service neutral at your meter main. Under this scenario, you would never know you had a problem and anyone coming into contact with the grounds or metalic objects they touch, think piping, could be killed very easily.

It is amazing to think that the billiant minds at the NEC ever thought this was OK. Even 20 or 30 years ago.

 

[MrMark]

You have it right now

 

[Hutchins Auto Repair]

You are really close. Without N/G bonding at the shed, if the neutral becomes open circuit at the shed, your 120V power will be open circuit and nothing will flow. However, if you have N/G bonding at the shed and the neutral goes open then the circuit can complete through the ground wires (and anything metalic they touch) back to the service panel in your basement and then back to the utility through your service neutral at your meter main. Under this scenario, you would never know you had a problem and anyone coming into contact with the grounds or metalic objects they touch, think piping, could be killed very easily.

It is amazing to think that the billiant minds at the NEC ever thought this was OK. Even 20 or 30 years ago.

Got it now, MrMark! Thanks again! By the way, my name is also Mark!

 

[MrMark]

the ground pin may dissipate static. I believe that is one of its three functions, lightning, static and stabilize the neutral voltage to Earth.

You are probably around the same age as me then.

 

[Hutchins Auto Repair]

Sure do hope it helps the RF, that would be great but I doubt it. Either way, I will post results. 52 years old, but still learning every day! As an auto mechanic, learning stuff all over again every day is the Norm!

 

[MrMark]

I doubt it too but give it a try. I'm not quite up there with you yet but our name was only popular for a decade or so it seems. You actually picked this up really fast. The grounding/neutral etc is not well understood, even by the people doing this for a living.

 

[nehog]

It is important to keep in mind that RF (static, noise) works very differently from power. Grounds for RF need to be low impedance, ground lines need to be kept as short as possible, larger wire is important.

That is why I suggested adding separate grounds to the fixtures to a ground rod. The ground in the feed is worthless for RF issues (but suitable for power needs and safety.)