50 Amp Power Panel

[newsomer]

I am replacing a power panel on our property. The old power panel only had 20 amp 120 volt recepticals. A friend who is a certifiex master electrician (now retired and out of state) inspected the panel and showed me it had 60 amp service. I have bought a panel box (Siemens TL137US) to install. The service is 4 ga three wire, two hot legs and a common. I know where to connect all three but where do I go with the ground bar in the box? Is it grounded to the panel box which is connected to the steel post in the ground? I found a grounding rod in the ground about eight feet from the post but I'm not sure if that's required if the system is grounded by the post.

[randallb]

I do not know the length of your run but you can buy 6-2 direct bury for 2.99/foot roughly. I am sure with some shopping you can do better. A ground is normally 1/2 the size of the powers and a 6ga would give you a little extra load capacity on the ground circuit. Just bury it separately from your current run and then tape the unused wires back inside the main panel and the tombstone/sub-panel. These 2 extra wires will give you the ability to add a light or other power source near the RV panel. Remember that a little white phasing tape will allow a red or black wire to be used as a neutral.

[vermilye]

wa8yxm wrote:
I agree that CODE requires a ground run back to the common ground at the service entrance... HOWEVER ,.....

I"d just drive two grounds at least 3 feet apart one on either side of the post and ground there. NOT CODE, but if done right the inspectors will never notice, at least the ones that dang near killed me won;'t notice. (long story exposed HOT wire)

The problem doing this is if the conductance of the earth between the new ground rods & the ground connection at the service entrance is poor, a fault to ground may not carry enough current to trip the breaker protecting the panel. Secondly, using the earth as a ground conductor can produce some "interesting" shock hazards during a fault.

While it may be difficult to do, running a ground conductor between the new panel & the service entrance (or, if fed by a sub panel, the ground buss in the sub panel" is the only safe way to change the panel to 120/240.

[newsomer]

Okay friends, thanks for all the info, admonitions, etc . . . I have enough to go from here. My plan, shut it down until I have it properly grounded.

[MrWizard]

I think you have a 220v three wire run to hots and a ground,
No neutral

No self respective electrician
Should have run a drop from the main service, with out a ground wire

If that is a neutral, the previous owner of the property did that run with out a permit

Sounds like you just recently acquired the property, and you want to use that for an RV 50 amp service

RVs set on steel frames and rubber tires , you want that ground for safety

As to whether you can drive a ground rod and ground that way or whether you must run a for grounds wire service
Distance from the service panel and pole, will be decided by local code,

If it's in conduit, a forth wire for ground can be pulled in
If it's direct burial cable them You need new cable if code requires the forth wire
You must have some kind of ground for safety

There is a ground rod now
But are things up to code ?
We don't know

[MEXICOWANDERER]

Your local government has a building code dept to inspect new dwellings to certify them.

It is FREE to visit this department

It is FREE for them to explain local building codes and make xerox copies to give to you.

When you have this copy flapping in hand you have the master document which over-rules comments and any contractor or "expert".

Further plan, whine, moan or celebrate, only after you have this document in hand and have read it.

This has to due with fire and liability insurance plus avoidance of code violations not budgets or personal opinion.

[rjniles]

Do not skip the ground wire back to the main panel. If you have a ground fault (hot wire touching a metal part of the RV, the earth ground is now low enough resistance to trip the breaker. And if you touch the metal you will get zapped. How badly zapped depends on how well you are grounded.

[newsomer]

Maybe I'm grasping at straws here now but I want to clarify something here. Not being a professional electrician I may have used the wrong description of my situation. I was wondering why something that was likely run in 2005 would be so shortsighted as to not include what at that time would be called best practice or at the very least code.

Let me try to explain in a little more detail. The wires run to the post are three 4ga wires, two hots, and one common, no fourth bare or ground wire. But, here's what MIGHT make a difference in all this, maybe not. The run is not connected to what I might consider the "Main Panel" but is run from two 60 amp paired breakers in the box containing the power company's meter. This box contains a main shut off for the house (manufactured home), the RV run, a workshop run, and breakers for some run I've yet to identify (likely for a well pump they never put in). As I said this may or may not change things for those in the know.

[newsomer]

ScottG wrote:
I wouldn't consider the ground back to the panel a waste at all. It's a very important safety measure you don't want to do without.

I wasn't calling the ground back to the main panel a waste, I was calling my purchasing a $150 box that would require hundreds more to make it safe.

[wa8yxm]

I agree that CODE requires a ground run back to the common ground at the service entrance... HOWEVER ,.....

I"d just drive two grounds at least 3 feet apart one on either side of the post and ground there. NOT CODE, but if done right the inspectors will never notice, at least the ones that dang near killed me won;'t notice. (long story exposed HOT wire)

[ScottG]

I wouldn't consider the ground back to the panel a waste at all. It's a very important safety measure you don't want to do without.

[newsomer]

Yeah I guess we'll see about having a local professional look at it but I'm not sure it's worth the cost to run the ground wire. What a waste.

[ScottG]

Just did this and had it inspected.
You need to run a ground wire back to the main panel and then you need to install TWO ground rods at your new panel. One should be 10 feet from the second and connected by a continuous, solid 8awg (or better) wire. The top of the ground rod must be below the surface.
This is all per the NEC.

[Old-Biscuit]

Have a LOCAL Electrical Contractor come out and give you an estimate.....what is needed and how it needs to be done.

50A is 2/Hot, 1/Neutral, 1/Ground

The 'Ground' will most likely need to have ground wire run back to main panel PLUS the new panel will probably need to be connected to the existing ground rod...and maybe another one ............

All depends on LOCAL Regulations/Requirements/Permitting


That is why it is best to have a LOCAL contractor have a look

[myredracer]

What you do will depend on whether this is used as a main panel or sub-panel. You may need two ground rods. Would be nice to do this yourself and save $$, but I think this is one of those cases where you are better off hiring an electrician to ensure it's all done correctly and safely.

You might try asking for advice on the Mike Holt electrical forum where electricians, inspectors, engineers, etc. hang out.