trying to cheap out need help

[mebedave]

Need a little help. I have a existing 60 amp panel in my pole barn underground wire size are 3 - #4 120 ft from pole. I’m remodeling the 40x80 pole barn and going to finish off 40x50 for a shop. What size breaker panel can I run off this 3- #4 I currently run my 300 amp wire feed welder, with lights on (not many) and other fab tools never had a problem, one man shop can only run a few tools at a time. I might put some kind of electric heat in too. R30 in walls and R49 in ceiling don’t need much heat and possible jacket like most of us I’m trying to save some money.
As a side note, lets just say I install a 200amp panel with this service feed so I have lots of room to wire shop as I want and later when money is not so tight I upgrade the service run if this #4 is too small (which by code I think it is). The #4's comes straight from the pole off a generator panel sharing lugs going to the house (house 200amp #2’s) I know I have code issues, not going to be inspected and I live in rural. But I would like to know best way do this and protect myself. Should I install some kind of a fused box of some kind at the gen panel to protect the #4’s from pole to shop? Thanks

 

[nehog]

N... wire size are 3 - #4 120 ft...

As a side note, lets just say I install a 200amp panel with this service feed so I have lots of room to wire shop as I want and later when money is not so tight I upgrade the service run if this #4 is too small (which by code I think it is). The #4's comes straight from the pole off a generator panel sharing lugs going to the house (house 200amp #2’s) ...

#1 Copper or AL? If copper you are good for 80 amps.

#2 You need to have a breaker rated for the wire size, so an 80 amp breaker at the source.

The size of the box is secondary to having that breaker at the source.

 

[mebedave]

#1 Copper or AL? If copper you are good for 80 amps.

#2 You need to have a breaker rated for the wire size, so an 80 amp breaker at the source.

The size of the box is secondary to having that breaker at the source.

First off Thank You! Secondly can someone please tell me what size breaker I need to protect #4 AL ?From what nehog is telling me I should have this breaker (size_____?) at the source,just to clarify that would mean at the power pole (meter) right?
I know this rubs some the wrong way to try and cheap out I normally always do things the right way, in fact I'm a over-killer big time! But money is very tight and I would like to get this shop wired and insulated cuz winter is very near 34 degree here! So if anyone have any more suggestion Hit Me!! Thanks

 

[mebedave]

found this link, it's helpful,but still need some advise. http://ths.gardenweb.com/faq/lists/wiring/2005015726007600.html

 

[theoldwizard1]

With AL and that distance, you are limited to 60A.

The statement "breaker at the source" means at the input to your sub-panel. If the other end of the cable ends inside the meter housing, you are good to go.

If you want to install a larger panel (say 200A) there is a way to wire the input through a different set of breakers (60A). This was covered in a recent post, but I can't find it

 

[theoldwizard1]

I'm not certain this will solve your first goal (cheap), but Square D does sell "load centers" (their term for a panel box) that come with no main installed (QO12024L125G Load Center I don't think the cover/door is included either) You can then buy the main breaker appropriate for the entrance cable (QOM60VH Circuit Breaker)

That panel holds 24 breakers (4 doubles) and has a max input of 125A. Bigger panels can NOT be downsized to a 60A main breaker.

 

[mebedave]

Ok I'm NOT GONE TO CHEAP OUT (100%) going to upgrade the 60amp service to 200amp and the #4 service feed to the shop. Sometimes even when $ is tight you just got to do whats right. SO!! Depending on where I bring the service into the shop, which I think it will be on the 80 foot side of the building. Its a 40x80 and i'm finishing off the back half. got to find my long tape to see how far the mid point of the shop is from the power pole but its real close to 140'. went to HD to check on direct bury feed, they have 4/0 4/0 2/0 miss marked (and they know it) at 1.83 per foot it's cheaper than the 2/0 2/0 i think 2/0 for 1.97 per foot. I'll go with a 200amp panel and going to go buy about 170' of that 4/0 before they fix that price. Ran over to Lowes it was 3.44 per foot same 4/0 service feed.
Yes it's AL, copper same size was close to 11.00 a foot Sorry you copper guys I'm cheaping out again and going with AL!!
Thanks to all that replied to try and help me cheap out above but... going to bite the bullet

 

[theoldwizard1]

Double check the rating of the insulation. THWN-2 is rated at 205A while THWN is rated at 180A.

IMHO, 200A service for a 1-2 man shop is overkill. How many times are you going to being using high power tools, simultaneously (exception may be a plasma cutter quick requires shop air) ? If you dropped down to a 125A panel, you could use #1/0 AL THWN-2 or 100A panel with #2 AL THWN-2.

Remember, the sum of the output breakers CAN exceed the main breaker capacity. Square D and other panel makers have multiple different configuration at 100A and 125A. You local big box store may not have them in stock, but I know they make panel boxes with that size mains that have 12-16 breaker positions.

 

[mtne]

Hmmm,

4/0 is good for 200A for a single phase dwelling service. 180A at 75deg Ampacity ratings are limited by the temp ratings of the lugs or device they are attached to............ would I actually worry about it? No. Would the insurance company use it to avoid payout in the case of a barn fire? Who knows. The silly things I think about sometimes.

Get that wire while you can! And protect it with a 150A breaker, you'll never load up that system enough to strain it with a regular shop. I prefer to use full size panels just so there's lot's of room, most of the smaller panels are limited as to how many full size slots are available.

I was going to suggest that you backfeed to a 60A breaker on a new main lug only panel if you were planning on going cheap. That would allow you the space and ability to get everything wired inside the way you want and not commit to the expensive feeders at the start.

Don't forget your ground rod and #6cu for the building if it's not already in place or if your moving locations.

 

[mebedave]

Double check the rating of the insulation. THWN-2 is rated at 205A while THWN is rated at 180A.

IMHO, 200A service for a 1-2 man shop is overkill. How many times are you going to being using high power tools, simultaneously (exception may be a plasma cutter quick requires shop air) ? If you dropped down to a 125A panel, you could use #1/0 AL THWN-2 or 100A panel with #2 AL THWN-2.

Remember, the sum of the output breakers CAN exceed the main breaker capacity. Square D and other panel makers have multiple different configuration at 100A and 125A. You local big box store may not have them in stock, but I know they make panel boxes with that size mains that have 12-16 breaker positions.

Wizard
I know its overkill, but I can buy the 4/0 wire and a 200 amp panel for just about the same price as the 100mp setup.

 

[mebedave]

Hmmm,

4/0 is good for 200A for a single phase dwelling service. 180A at 75deg Ampacity ratings are limited by the temp ratings of the lugs or device they are attached to............ would I actually worry about it? No. Would the insurance company use it to avoid payout in the case of a barn fire? Who knows. The silly things I think about sometimes.

Get that wire while you can! And protect it with a 150A breaker, you'll never load up that system enough to strain it with a regular shop. I prefer to use full size panels just so there's lot's of room, most of the smaller panels are limited as to how many full size slots are available.

I was going to suggest that you backfeed to a 60A breaker on a new main lug only panel if you were planning on going cheap. That would allow you the space and ability to get everything wired inside the way you want and not commit to the expensive feeders at the start.

Don't forget your ground rod and #6cu for the building if it's not already in place or if your moving locations.

Mtne
Do you mean protect it with a 150amp breaker at the meter, add a disconnect w/breaker?
Just to clarity this is a underground service from the meter which is located on a power pole in my yard 140' from the shop and the meter/pole sets 60' from the house. The house has a 200amp panel located in the garage. I do not want to run a sub-panel from that house 200amp main it's full, lots of work and cost to do that. At the meter the existing shop 60amp and the house 200amp shares a lug. I have a lug splitter that will handle the house 2/0 and the new shop 4/0 this split lug is inside an existing Generator transfer switch(rated 10,000 amps) just below the meter. Ok I know I'll get some "that's not to code" comments and that OK hit me. Just so you know this is on a farm and we do things a little different out here. Don't get me wrong I want to be safe.

 

[mtne]

So if I'm understanding correctly. Do you have room for two double pole breakers just after the meter or are you double lugging off of the 200A main disconnect? If you have room for two main disconnects I'd put a 150A main breaker in and run your new service just like a new service. In which case if you got the 4/0AL wire and it's coming from the meter, it is a service and could be protected at 200A. Where as if it was feeding a sub panel I would choose to protect it at 150A. Either way it's much more than you'll likely need. I did the same for my dad at his place so that he has two panels on separate main breakers from the meter going to different parts of his property. If your double lugging that's not a set up I'm comfortable advising on with out seeing the set up.

 

[mebedave]

So if I'm understanding correctly. Do you have room for two double pole breakers just after the meter or are you double lugging off of the 200A main disconnect? If you have room for two main disconnects I'd put a 150A main breaker in and run your new service just like a new service. In which case if you got the 4/0AL wire and it's coming from the meter, it is a service and could be protected at 200A. Where as if it was feeding a sub panel I would choose to protect it at 150A. Either way it's much more than you'll likely need. I did the same for my dad at his place so that he has two panels on separate main breakers from the meter going to different parts of his property. If your double lugging that's not a set up I'm comfortable advising on with out seeing the set up.

Mtne
Thank you, There is no disconnect at the meter just a gen. transfer switch that has no breakers. Inside that switch are existing double lugs that feed the hots for the shop and the house, the neutrals for shop and house run up into the meter box and are double lugged in behind meter.
I could call the power company, I was hoping I could keep it simple and just hook it back up as before, accept with larger shop feed. Power company most likely well what to run more power poles across my yard and separate meter for the shop. I'm not liking that idea, more poles in yard and another electric bill... that is.

 

[mtne]

Inside the cover should be a diagram indicating what those lugs are rated for. Good chance that while yes there already lugs in place that are large enough for 200A out to a shop, they are not intended to serve two services. Of course that is just a guess, and it may be permissable to do it that way. Either way I'd want to know for sure before dropping the money on some new feeders.

In the mean time get a 200A main breaker or main lug panel and backfeed through a 60A breaker. That will give you the freedom to proceed inside........... just my take on it. Likely a lineman would know better about it. Maybe go so far as to google the equipment model numbers and see what info comes up.

 

[mebedave]

Inside the cover should be a diagram indicating what those lugs are rated for. Good chance that while yes there already lugs in place that are large enough for 200A out to a shop, they are not intended to serve two services. Of course that is just a guess, and it may be permissable to do it that way. Either way I'd want to know for sure before dropping the money on some new feeders.

In the mean time get a 200A main breaker or main lug panel and backfeed through a 60A breaker. That will give you the freedom to proceed inside........... just my take on it. Likely a lineman would know better about it. Maybe go so far as to google the equipment model numbers and see what info comes up.

Mtne
thanks again you have been a big help. I did talk to my power company today told him everything that is existing and how I'd like to upgrade to 4/0 wire feed and new 200 amp service to the shop. I explained to him the transfer switch non-breaker lug sharing that i have existing and that i would like to switch out the feed to the shop for the 4/0 and share lug as existing. To my surprise he was aware of the gen. transfer switch i had including the name brand (said he has the same one at his house) and that I could go on as planned and change to the larger 200amp and wire and share lug. I told him i feared he would force me to do a bunch of upgrading and possible 2nd meter to shop which means more money, he told me no way he would and in fact that transfer switch i have is a very good one and it will handle my needs very well.

 

[mtne]

Excellent! Now one last question..... you made it sound like there's no main disconnect before those lugs....... yes? So you'll be landing those hot?

 

[mebedave]

Excellent! Now one last question..... you made it sound like there's no main disconnect before those lugs....... yes? So you'll be landing those hot?

Yes Mtne that was the plan, is that bad?

 

[mtne]

Yes Mtne that was the plan, is that bad?

Only if you do it wrong............... Not sure how much working room you have to do it and how comfortable you are around hot equipment. Depending on how far you are from the transformer and stuff like that determines the potential for arc flash.

So, wear your PPE and be slow and methodical. As always work and finish your dead end connections first. And make sure there's no load on and connection your making while hot.

And don't forget the nolaox for the aluminum ..............

 

[mebedave]

Only if you do it wrong............... Not sure how much working room you have to do it and how comfortable you are around hot equipment. Depending on how far you are from the transformer and stuff like that determines the potential for arc flash.

So, wear your PPE and be slow and methodical. As always work and finish your dead end connections first. And make sure there's no load on and connection your making while hot.

And don't forget the nolaox for the aluminum ..............

Thanks I'll be alright, have good space and no problem working with hot