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Cyndi 04-19-2008 11:16 PM

Help if it's not too late!!
Hi Guys- My name is Cyndi and I have started an electrical job for the first time. I hope it's not too late to make any needed corrections.

I run an animal rescue and needed power in my animal barn/garage/shop. The building is 100 feet from the main house panel. The building is 36'x50'. I will be running heat lamps, trough heaters flourescent lights and some power tools.

I ran 3 #8 wires from the main panel next to the house. One white, two black. This was from a 40 amp breaker in the main panel.

From reading some of your input, I am understanding that #1, I should have also run a green #8 wire from the main panel as well? I didn't do that so is it o.k. to just put a grounding rod in at the new sub-panel???

#2 I also did not isolate the ground wiring for the outlets from the neutral wires. There was only one bar in the panel. I guess I need to buy another bar and install it in the panel and separate the ground wires from the neutral wires??

I do not have one breaker that shuts off all power to the panel except for the one in the main panel by the house. Do I need to make that change too???

I'm glad I found your site. Better late than never, huh??

P.S. The outlets all work fine at this point but I want it to be safe. I haven't finished the lighting. I'm working on the conduit runs.

Thanks for your consideration. Cyndi

220/221 04-19-2008 11:31 PM


I didn't do that so is it o.k. to just put a grounding rod in at the new sub-panel???

#2 I also did not isolate the ground wiring for the outlets from the neutral wires. There was only one bar in the panel. I guess I need to buy another bar and install it in the panel and separate the ground wires from the neutral wires??

I do not have one breaker that shuts off all power to the panel except for the one in the main panel by the house. Do I need to make that change too???

No, yes and yes.

The first two issues are more important from a safety standpoint.

Stubbie 04-20-2008 12:01 AM

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Hi Cyndi

It is preferred to run four wires...2 hots (black), one white (neutral) and a insulated green equipment grounding wire. However if you are not required to run 4 wires by local code or if you are under the 2005 NEC electrical code then you are allowed to run 3 wires as you have already done. I wish you would have ran a 60 amp feeder to your electrical panel in the animal shelter.

Please note that if you have any other metallic paths in addition to the electrical feeder to the sub panel like water lines or phone lines to the shelter you must run four wires to your shelter sub-panel.

At any rate if you elect to keep the 3 wire feeder you do not separate the grounds and neutrals but you must install the bonding means in the single neutral bar. This is often a green screw that goes into the neutral bar and threads into the back of the metal panel. If you tell me the maker of your panel I can help you with the bonding if your not sure.
You will need a ground rod probably 2 of them. You will run a #6 copper out to those ground rods and use ground rod clamps to bond the wire to the rods.

We can link you to photos of the needed materials if you like.

Be sure to use gfci protection on your receptacles. Here is a diagram of what you should have...ask lots of question about anything you are unsure of....

Cyndi 04-20-2008 09:49 AM

A Great Big Thanks!!!
A great big THANKS to you Stubbie!!!! Your information was invaluable to me. I wish I had run #6 wire out to the barn with a larger breaker in the main panel as well. I am trying to decide whether I should pull the #8 out, install #6 and if I am to do that I may as well run a ground wire too!!! A lot of work but I do want it to be safe!!!! The panel is a 125 and it does not have a main shut off either. There is no room in the panel to put a shut off breaker as I have used most of the breakers already adding the slim jims to accomodate what I already have planned.

I may need to start with a larger panel, or change it in the near future. It would be smarter to change it now when I only have the left side of the garage wired in I guess.

I have 6 outlets on the left wall on their own circuit. The outlets will most likely have water trough heaters going with additional lamps for heat at times in the winter. The lamps usually have 150 -250 watt bulbs in them to warm the baby goats that are being born. The trough heaters are anywhere from 500-1250 watts each and there will be 2-3 on that same circuit.

All of the ceiling lights on the left, middle and right of the barn are flourescent and they are on their own circuit.

The right side of the barn is to be the same as the left with 6 outlets on their own circuit.

The rear of the barn will have 5-6 outlets on their own circuit for a shop area for light wood working projects. I have also run a 220 plug for my table saw that requires one.

From that same panel, there are three other circuits that run to outdoor pastures that have water trough heaters, lighting and an outlet at each of three locations. They are functional at this time and were used this past winter with no trouble.

I thought I was ready to wire in the barn, but now I am wondering if I should get a larger panel and do the things that you experts would do if it were your barn.

Thanks for your consideration and the information/drawing. You are great Stubbie!!!


Stubbie 04-20-2008 10:06 AM


You do not need a larger panel. 125 amps should be more than enough for future growth. You would most likely have to upgrade the main panel at your house before you would ever think of upgrading the shelter sub-panel.

What size service in amps do you have for your home?

You should have a disconnect for the panel that will break both the hot conductors of the feeder. If you could give me the model# and maker of your panel I can see if it will accept a main breaker kit or backfed breaker for your disconnect. You have what is called a main lug panel at present sometimes these can convert to main breaker or backfed breaker. Or you can have a separate disconnect from the panel itself.

It is important to know how many heaters you will be operating and the overall load you expect at the shelter in order to properly size the feeder.

If you have that 125 amp panel full of circuits you likely have way more than a 40 amp feeder can support. Give me a few minutes to look at your load information you posted. I'll post back in few minutes.

Cyndi 04-20-2008 10:36 AM

More Info
Hey Stubbie! Thanks for the quick response. I checked out the information that I think you wanted. We have a panel and meter on a pole outside that is 200amps. The breakers within the panel are a 50, 20, 30 and 40. The 40 going to the barn.

Then there is a 200 amp panel in our man. home, being fed from that pole panel as well.

I ran the #8 wire from the outside pole panel on the 40 amp breaker.

The brand of panel is a Murray. Where is the model # located?? Is it stamped into the metal back of the panel or is it on the paper label. If it is on the label, like a dummy, I put the breaker label sticker over that and when I try to remove it, it peels the underlying label too.

Thanks, Cyndi

Stubbie 04-20-2008 10:59 AM

Ok... there is no way to run all those heat lamps and heaters on one branch circuit for cord and plug.

If you are running a 15 amp branch circuit and your outlets are duplexes (2 outlets) one 250 watt lamp and one 1250 watt 120 volt heater is all you operate on one breaker from one duplex receptacle. You have six duplexes it sounds like on one circuit!! A 15 amp breaker can operate 1800 watts of non-continuous load. One lamp and one heater is 1500 watts if you use the maximums that you posted. If you try to operate all those heaters and lamps on one branch circuit whether it is 15 or 20 amp you will be grossly overloaded!

Example: A 20 amp branch circuit will operate 2400 watts of non-continuous load. You have 6 duplexes 3 have 150 watt heat lamps and the other 3 have 250 watt heat lamps these are continuous loads unless you have them on timers. In addition you have 2 500 watt heaters and one 1250 watt heater at 120 volts on a thermostat. 3x150=450 watts 3x250=750watts which equals 1200 watts of continuous load. then you have 500x2 = 1000watts + 1250 watts = 2250 watts of non-continuous load. The circuit requires conductors rated 125% of the continuous load plus the non-continuous load. So you need conductors rated for 3750 watts or 31 amps. Can't do this on one 20 or 15 amp branch circuit.
The outside heaters in the pastures plus what you have in the shelter will not be supported by 40 amps if you operate all this in the winter. The rest of the year should be ok but still that will not do what you need.

You need to pull in a 60 amp feeder using #6 thwn conductors H-H-N and a #10 ground.

If this is what you choose then we need to go over what you need to do to connect the 4 wire feeder to your 125 amp sub.

Cyndi 04-20-2008 11:02 AM


The barn panel is an 8 breaker slot panel. Two are being used for the 220 saw outlet. That leaves 6. I bought slim-jims so now I have 12 besides the 220 breakers. Six are being used for the outside outlets, lights etc. That leaves me with 6. I have one of those six hooked up to the six outlets for the left side of the barn. That leaves me with 5 left. Two other breakers are obligated for the rear circuit and right circuit of the garage. That leaves me 3. I need one for all the flourescent ceiling lights which leaves me with 2 extra breakers in the panel.

I guess I should plan to pull the #8 wire out, put a 60amp breaker in the outside pole panel and run #6 wire to the barn???? I should have hired an electrician!!!!!!!!!!!!!!!!!!!!!!!!!!! Actually it is fun to learn this stuff so if I make some mistakes along the way (as long as they are fixable), I guess that is part of the process.

Thanks, Cyndi

Stubbie 04-20-2008 11:06 AM

Do you still have the box the panel came in?

Use 2 20 amp breakers and split the 6 duplexes 3 on each breaker. Do not put more than one 1250 watt heater on either circuit. You will have 2400 watts to work with on a 20 amp branch circuit.

For ease of installation consider replacing your main lug panel with a 100 amp or 125 amp main breaker panel.

Cyndi 04-20-2008 11:15 AM


I just got your load calcs. Wow!!! Anyway, The baby pens are in the planning stage and I could just put 4 pens that have one water trough for 2 pens making a total of 2 water troughs needing one heater each at 500 watts each. Then I would need a lamp for each pen (4) and could put 150 watt bulbs for heating an area in each pen for the babies to keep warm. This would all be on one circuit. The same would apply for the circuit on the right side of the barn. Would that work??? All my breakers are 20 amp with #12 wired circuits-grounded.


Stubbie 04-20-2008 11:18 AM

Also using #6 thwn copper will allow you to place it on a 70 amp breaker. the wire is rated for 65 amps but there is no 65 amp breaker so you can move one size up to a 70 if you wish.

Cyndi 04-20-2008 11:24 AM

Stubbie- I do not have the box that the panel came in. The panel was installed last year with the exterior pen wiring. I am just now getting to the barn lighting as the old barn caved in from all the snow this year and the new barn was completed last week. Thank goodness the panel wasn't damaged but here I am wondering what to do next to make it all work out the way that it should. You are a great help and I do appreciate all of your input. I am willing to do whatever it takes to make the system work the way that it should. So, you just let me know what I need to do and I will do it!!! Thanks. Cyndi

J. V. 04-20-2008 11:25 AM

Did you run your feeder wires in conduit or is it direct burial cable? If it is in conduit you may have enough room for the EGC (green ground wire) or possibly run larger conductors. Stubbie is taking good care of you and I encourage you to continue working with him on this project.
Electrical safety is paramount to most of the pros on this site. Operational issues are important too. It looks as if you are in the operational mode now so don't hesitate to ask more questions. There are others available if Stubbie is not.

Stubbie 04-20-2008 11:27 AM

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As long as you understand how to balance the loads so you don't overload the breaker that is fine.

You need a disconnect of some kind at the panel. A main breaker panel 100 amp or 125 amp is the simplest. Its is ok to feed this with a 60 or 70 amp feeder with the protecting breaker at the pole panel you mentioned. The breaker in the shelter sub-panel will simply be your disconnect.

Your going to need to separate the grounds and neutrals using a 4 wire feeder.
This usually requires purchasing a ground bar kit that will install in the predrilled swaged holes in the back of the panel. Simple installation is required using a couple screws.

Here is another diagram of how it will look...

Cyndi 04-20-2008 11:29 AM

Stubbie- You mentioned replacing the main lug panel with a 100-125 breaker panel. What does that mean. The main panel on the pole is a 200 amp panel??? I don't get it. Thanks, Cyndi

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