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Author Topic: How to Install 50 Amp Service at Home?  (Read 8137 times)
Depewtee
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« on: July 18, 2010, 10:44:50 AM »

Hi All - The heat has finally won out, so it is time to install a 50 amp outlet at the house so I can plug the bus(es) in to shore power.  It will be nice to have A/C and lights when working on the bus(es) without having to run the generator.  I need advice on how to wire the 50 amp outlet.  Fortunately, I have a good power source near where I am parking the bus(es).  I have a 60 amp 220 volt circuit that used to feed the swimming pool pump and related accessories.  The pool has been gone for several years and when I removed the pump I installed a breaker panel.  I have yet to install anything in that breaker panel until now.  I went to Home Depot and bought a "rainproof" 50 amp outlet.  Although I am really good with 12 volt systems, I am a bit green when it comes to 110/220 volt.  Here is a picture to show you what I am working with



Here are my assumptions - please correct me if I am wrong.

1. The red and yellow arrows point to the supply (black) wires.

2. The blue arrow points to the neutral (bare) stranded wire.

Here are the facts.

1. When I place a volt meter across the two supply lines I read approximately 220 volts.

2. When I place a volt meter from either supply line to the neutral I read approximately 110 volts.

From here I am not real sure what I am doing  Smiley.

I believe I need to connect the neutral wire to the terminal highlighted by the green arrow.  I would have done this earlier, but it is too short.  Is this correct and any thoughts on how to extend the wire?

There is no ground wire in my breaker panel.  Should I run a wire from the breaker panel to earth ground (i.e., drive a metal pole in the ground)?  Also, should I hook the ground wire from my 50 amp outlet (purple arrow) to this earth ground?

I bought a 50 amp breaker (see picture).  Do I run a wire from each of the two terminals on the breaker to the 50 amp outlet?  According to the instructions that came with the outlet I am to hook the neutral wire up to the terminal directly below the ground and the supply lines go to the other two terminals (the "side" terminals).



Am I on the right track?  What would you guys/gals do different?

Thanks in advance,

Brian S.


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Brian Shonk
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« Reply #1 on: July 18, 2010, 11:03:34 AM »

What you have is two hots and a ground but no neutral.  That was fine for the pump which was only 220, not 110/220.  You need to pull another white conductor back to the main panel.

If it's in conduit all the way to the main panel, it is easier to pull all the wires out, then pull them back with the additional neutral conductor.

From the looks of the grounding conductor, I'm guessing that it is not conduit all the way but rather a cable of some kind, probably Type SE.  If that's the case, you will have to replace it all. The neutral should not be bare, only the ground can be bare.

You are also going to need an additional ground bus in your new panel and to isolate the neutral from the case, probably by removing a screw or strap, I can't see it in the pic.
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« Reply #2 on: July 18, 2010, 11:36:15 AM »

If this was wired right to start with the bare wire should be a ground, not a neutral.  A 220 volt only circuit has a ground and no neutral.  The ground and neutral are tied together at the main panel so you will get 110 volts from got to ground.  In the old days, appliances that needed both 220 and 110 like dryers just used the ground for neutral.  This is no longer allowed for new installations and new dryer outlets need a seperate neutral.

Len is right that you need a neutral.  You may only be able to get that size wire in black.  It is okay to use a black wire for neutral, but you must wrap both ends with white tape to differentiate it from the hot wires.  I would suggest when you pull your neutral that you disconnect the flexible conduit and straighten it out to make the pulling easier.  They make a special gel for pulling wire that you may want to buy for this job.

If you have any doubts about this, hire an electrician!
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Depewtee
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« Reply #3 on: July 18, 2010, 12:46:37 PM »

Thanks for the replies Len and Belfert.  Looks like no A/C in the bus today.  I have some flex conduit and 6 THHN wire.  Would this wire suffice to go from the breaker panel to the 50 amp outlet?  If so, I will go ahead and button it up and work on running a neutral from the house breaker panel to this one.

I just took a couple of pictures of the house main breaker panel.  Will I be able to accomplish what I want with this setup?  If so, where do I split the neutral and ground?  If it can be done, I will pull the additional wire needed for the neutral and check into finding an electrician.



The 60 amp breaker that went to the pool pump is the bottom leftmost breaker.



Thanks again,

Brian S.
« Last Edit: July 18, 2010, 01:42:39 PM by Depewtee » Logged

Brian Shonk
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« Reply #4 on: July 18, 2010, 01:47:55 PM »

...  You may only be able to get that size wire in black.  It is okay to use a black wire for neutral, but you must wrap both ends with white tape to differentiate it from the hot wires.  ...


Sorry, this is not true in the size you will need.  From the 2008 code:

"200.6 Means of Identifying Grounded Conductors.

(A) Sizes 6 AWG or Smaller.
An insulated grounded conductor of 6 AWG or smaller shall be identified by a continuous white or gray outer finish or by three continuous white stripes on other than green insulation along its entire length. ...

(B) Sizes Larger Than 6 AWG. An insulated grounded conductor larger than 6 AWG shall be identified by ... [goes on to say end-marking is permitted]"


(Folks new to electrical work should note that the code calls the neutral the "grounded conductor" whereas safety ground is called the "grounding conductor.")

In #6, you need to use white, gray, or white-stripe wire, which should be readily available anyplace where #6 is sold in other colors.

Also note that if this is a manufactured cable assembly such as NM which has been fished through a conduit, as Len speculated, then the entire item must be replaced, you can not simply run a loose neutral along side it.

-Sean
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« Last Edit: July 18, 2010, 01:51:36 PM by Sean » Logged

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« Reply #5 on: July 18, 2010, 02:28:42 PM »

Every breaker panel or pony panel I have ever worked on had neutrals all on one buss, and grounds all on a separate bus.  Is it to code for the neutrals and grounds to all be mixed up on one buss like that?  Also there are a ton of lugs meant for heavy gauge wire with many 14 gauge neutral and ground wires stuffed into  them?  I didn't that was allowed by code either.

Brian
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« Reply #6 on: July 18, 2010, 03:02:41 PM »

Every breaker panel or pony panel I have ever worked on had neutrals all on one buss, and grounds all on a separate bus.  Is it to code for the neutrals and grounds to all be mixed up on one buss like that?


Grounds and neutrals are tied together in the main service panel.  AFAIK, there is no code provision that would require them to be on separate buss bars IN A MAIN PANEL.

However, in a sub panel, neutrals must be isolated from ground.  The ground-neutral connection must exist in only one place, and that is generally the main panel (although in some applications it might be at a service entrance or at the transformer where the neutral is derived, in which case all panels need isolated neutral busses).

That said, I think it's sloppy.  For one thing, it makes it more difficult to find the neutral or ground you are looking for.  For another, it means you can not install a panel upstream of this one, thus making this panel a sub-panel, without having to rewire the whole panel to isolate the neutrals.  Therefore I prefer to install an isolated neutral buss in every panel, including the main panel, and then tie that buss to the ground buss wherever appropriate with a strap.  That way the strap can be removed later to convert the panel to a sub-panel.

Quote
Also there are a ton of lugs meant for heavy gauge wire with many 14 gauge neutral and ground wires stuffed into  them?  I didn't that was allowed by code either.


The code does not stipulate, other than to say that the device must be installed according to its listing.  So if a lug is "listed" as suitable for, say, #8-#10, then, no, you can not put a #12 in that lug.  The listed wire sizes for each lug should be spelled out in the installation instructions for the panel.  Manufacturers will list connectors for multiple conductors, so, for example, you might see a wire nut listed for two #10 or three #12 or one #10 and one #12, etc.

It is a code violation (and dangerous) to stray outside the listed usage, yet I see it all the time.  My blog is replete with photographs of dangerously wired campground pedestals.

-Sean
http://OurOdyssey.BlogSpot.com
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Depewtee
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« Reply #7 on: July 18, 2010, 03:15:05 PM »

A little history on the house.  It was built in 1976 by the family that owns one of the largest electrical contracting businesses in town.  They do residential and commercial - all the way up to large condominium complexes.  I guess codes were a little different 35 years ago.

Sean - you are very perceptive, it is a manufactured cable assembly that has the two large black wires (4 AWG maybe....) and the bare stranded wire.  It is about a 100 foot run from the main breaker panel to where I want to install the 50 amp outlet.  My ultimate goal though is to run the wire underground and come up on the other side of the bus - probably requiring another 30 feet. I am afraid to look at the Home Depot website to see how much the wiring is going to cost  Shocked.  I do want to be able to plug in the bus(es) really bad, so looks like I will be spending some time in the attic running new wiring.  Any other advice is appreciated.  Looks like I will be finding an electrician to make the final connections.

Still wanting to "button up" my work for the day.  Does the following diagram look correct (power is disconnected at the main panel)?  What gauge wire should I be using here?  Is 6 AWG big enough, or do I need to go with something larger?



Brian S.
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Brian Shonk
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« Reply #8 on: July 18, 2010, 03:22:55 PM »

Sean - I posted the above reply at the same time you were making your second post.  The history of the house was not intended to be a response to your post (I had not seen it yet).  I agree it looks sloppy to me, but I hope it is done within code (I can't imagine the original owner straying from code on his own house).  This is all starting to make a little more sense to me.  

1. I need to run a whole new set of wires from the main panel to the subpanel (a manufactured cable sounds in order).

2. I will tie the grounded and grounding wires (the white and the green) into the sloppy bus on the main panel.

3.  I will proceed with wiring the 50 amp outlet per my diagram above?Huh

Brian S.
« Last Edit: July 18, 2010, 03:26:12 PM by Depewtee » Logged

Brian Shonk
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« Reply #9 on: July 18, 2010, 04:50:28 PM »

Hold on!

I think you are risking energizing the coach chassis with your proposed wiring. And others may use stronger language to declare the coach will be live.

That is fancy speak for an electrocution hazard, touch the coach and get a thrill.

You have no neutral in that box. You should not proceed until you do.

Just because the circuit works, doesn't mean it is safe!

happy coaching!
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« Reply #10 on: July 18, 2010, 05:23:27 PM »

Buswarrior,

Thanks for the concern.  I only propose making the connections from the subpanel to the 50 amp outlet.  The subpanel is not hot - I have disconnected it at the main panel until I (or an electrician) sort this mess out.

I just went to Home Depot to price wire.  They closest they had was two 6 AWG wires, a 2 AWG wire, and a ground manufactured together.  A 125' roll was $190.00.  I am thinking the 6 AWG wire is not big enough.  All wires were copper.

Brian S.
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Brian Shonk
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« Reply #11 on: July 18, 2010, 05:26:15 PM »

1. I need to run a whole new set of wires from the main panel to the subpanel (a manufactured cable sounds in order).


Yes, and note that, per your earlier thought, there are cable types that are rated and approved for direct burial.  For 50-amp service, you need a "6/3-8/1" cable minimum, or "6/4".  For runs longer that about 100' or so, you might even think about going up a size to #4.  "6/3-8/1" refers to a cable assembly with three #6 wires (two hots and a neutral) and one #8 wire (safety ground).  The ground is permitted to be one "trade size" smaller than the current-carrying conductors, which means a #8 is permitted for a #6 installation.  In practice, many cable manufacturers just use four of the same size, which would be "6/4."


Quote
2. I will tie the grounded and grounding wires (the white and the green) into the sloppy bus on the main panel.


Correct.

Quote
3.  I will proceed with wiring the 50 amp outlet per my diagram above?Huh


Looks right to me.

Now that we're all clear on what you need to do to get this right, which is going to be a huge project, let me offer a "temporary, interim" solution so you can get some A/C out to your bus.

I will give you two choices, neither of which meets the full requirements of the code.  And thus I need to issue the following disclaimer:

It is always advisable to follow all applicable codes in all situations.  Advice you read on the Internet, including mine, should be taken strictly as a guide and you must at all times use your own judgment when working with electricity.  Electricity can be lethal and you or someone else can be killed or seriously injured if an installation is not done correctly and in observance of all safety practices.  I can not and will not be responsible for anything that might happen as a result of following any instructions I provide here.  When in doubt, hire professional help.

Ok, with that out of the way:

Option 1 (100% safe):  Put a 50-amp, single-pole breaker in the main panel.  Re-designate one of the two black wires as "neutral" and mark it at both ends with white electrician's tape (make absolutely certain you have the same wire so designated at each end..  Bypass the sub-panel at the end of the conduit (using it strictly as a junction box).  Now wire the single black wire to BOTH hot terminals of your 50-amp receptacle.  This means you will need to get a lug or other junction device to splice the incoming #6 hot to two outgoing #6 hot wires from the subpanel to the receptacle.  Splice the redesignated "neutral" wire to a length of #6 to the neutral terminal of the receptacle, and splice a #8 ground wire to the existing bare copper ground and run it to the ground terminal of the receptacle.  This will give you 6,000 watts of power to the bus, a single 50-amp, 120-volt leg spread across both hots on your shore cord (as opposed to the full 50-amp service, which is 12,000 watts, 240 volts, with a separate hot to each leg of the shore cord).  That ought to get you at least two or three air conditioners running.

Code issues for option 1: Not permitted to end-mark #6 wires for neutral use.  Sub-panel use as a splice box is not kosher without removing all innards and replacing cover with plain dead-front.  L14-50 receptacle not permitted to be used for 120-vac single-phase service.  However, none of these is a real safety hazard for temporary use.

Option 2 (some risk involved):  Make sure that the conduit between the sub-panel and the main panel is non-conductive (looks like PVC to me).  If this is not the case, you must not use this method.  Use a two-pole breaker in the sub-panel.  Run one black and one red #6 from this breaker to the two hot terminals of your receptacle.  Now wire separate #6 neutral (white) and #6 or #8 ground (bare or green) wire from the respective terminals on the receptacle to the sub-panel.  Connect both of these to the single existing bare ground wire.

This is important:  If that bare ground wire is #6, the two-pole breaker can be 50 amps.  If it is #8, then you will need to drop down to 40 amps.

This will get you either 9,600 or 12,000 watts of power on two hot legs.

Code issues for option 2:  Ground and neutral should really be separate all the way back to the main panel.  A wire used for safety grounding should not carry current under normal circumstances.

Safety issues for option 2:  Any alternative ground path between the receptacle and the main panel will carry some of the neutral return current (for example, the building masonry itself).  If enough current finds this path, any portion of the return path can present a shock hazard.  With a non-conductive masonry building and a non-conductive PVC conduit, there should be no alternative path available and the risk should be small.

FWIW, we plug our bus into 240-volt welder and dryer outlets with no neutral return all the time.  I carry a variety of plugs with me to make adapters for this purpose as needed.  This always presents a small risk, since neutral current is now being carried on the ground system, but it works, and in the middle of a disaster we consider it acceptable.  Clothes dryers used to be wired this way routinely before the code changed a decade or so ago.  I would never consider making such an installation permanent, but in a pinch it can be the difference between livable and non-livable conditions in a rig.

If any of that is unclear, please ask for help.  Don't bother asking a licensed electrician to do either of those things, because  I can't imagine anyone with a license at stake would do it.  And, as I said, they are offered as options to get you by, with the understanding that you will be making a proper and code-compliant installation shortly.  (In the code universe, BTW, the definition of "temporary" is no longer than 90 days -- beyond that, you need to make a permanent installation following all codes.)

HTH,

-Sean
http://OurOdyssey.BlogSpot.com
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« Reply #12 on: July 18, 2010, 05:33:38 PM »

Sean, it looks like the wiring in his breaker panel is larger than 6 AWG which is why I suggested he might not be able to get white cable if he were to use the same size cable.

Depewtee, from the picture it looks like you have a conduit at least part of the way.  You generally can't use jacketed NM type cable inside aa conduit unless you have plenty of extra space in the conduit.  I'm surprised Sean didn't mention this.
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« Reply #13 on: July 18, 2010, 05:51:33 PM »

The wire that is currently there is jacketed.  It used to be exposed running down the side of the house, but when I took the pool pump out I ran the jacketed wire inside the conduit (just on the outside of the house - it is still plain jacketed wire in the attic).  I just looked in the attic (should have taken a camera or pencil/pad) and the wire says Hatfield Hatvinol 3/0 6 AWG Stlye XHHW CDDRS.

Brian S.
« Last Edit: July 18, 2010, 06:06:45 PM by Depewtee » Logged

Brian Shonk
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« Reply #14 on: July 18, 2010, 06:41:50 PM »

Sean, it looks like the wiring in his breaker panel is larger than 6 AWG which is why I suggested he might not be able to get white cable if he were to use the same size cable.


Looked like #6 to me (and would be the correct size for the 60-amp pool equipment), but as you know it is hard to tell from a photo.  However he has confirmed it to be #6.

Quote
Depewtee, from the picture it looks like you have a conduit at least part of the way.  You generally can't use jacketed NM type cable inside aa conduit unless you have plenty of extra space in the conduit.  I'm surprised Sean didn't mention this.


Also did not look like NM to me, which generally would not be black/black/bare.  Again confirmed (more in a moment).  That said, bear in mind that many jacketed cables can be run in conduit or raceway without any further de-rating (beyond what is called for by the individual insulated conductors).  This is a byzantine subject and it is always best to consult the actual fill tables.  You are correct, some jacketed cables require more raceway space than individual conductors of the same type.

The wire that is currently there is jacketed.  It used to be exposed running down the side of the house, but when I took the pool pump out I ran the jacketed wire inside the conduit (just on the outside of the house - it is still plain jacketed wire in the attic).


Ahh, that explains it.  I was wondering why that was white PVC mated to seal-tight.  Generally, electrical PVC is gray, not white.  And non-metallic conduits can not be terminated at metallic boxes.  When you re-do all this, you should ditch the white PVC and use approved materials and fittings.

Quote
I just looked in the attic (should have taken a camera or pencil/pad) and the wire says Hatfield Hatvinol 3/0 6 AWG Stlye XHHW CDDRS.


OK, I think some of this is backwards.  What it probably says is "3 CDRS 6 AWG Style XHHW" which means the cable assembly has "3 conductors of #6 AWG (American Wire Gauge)" of type XHHW which is a high-temperature, flame-retardant, cross-linked polyethylene insulation.  There should also be a cable assembly type such as "SE" (service entrance) marked someplace.

It's all academic, really, since it is not suitable for what you want to do and you will need all new cable from the main panel all the way to the receptacle.  As I wrote earlier, this will need to be at least three conductors #6 and one #8 ("3 CDRS 6 AWG-1 CDR 8 AWG").

Again, what you already have in place can be made to work temporarily, with caution.  But all of this will need to be re-done to get a true 50-amp service out to the bus safely.

-Sean
http://OurOdyssey.BlogSpot.com
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