Situational Advice

Reply

  #1  
Old 02-07-20, 12:15 AM
N
Member
Thread Starter
Join Date: Feb 2020
Posts: 5
Received 0 Votes on 0 Posts
Situational Electrical Advice

I have some questions I am trying to knowledge myself in for my house so bear with me on the length as I want to provide as many details as I can.

First what I have going on:

I bought a house in the country and want to do some upgrades but need to know the reality Iím faced with.

I have the following electrical setup - I have a pole with my transformer about 40-50 ft to a main panel which is a Eaton MBE2040PV200BTS where my meter is located. Inside I have a 150amp breaker that feeds 3/0 copper up the hill a couple hundred feet to a secondary panel. This panel has a 100amp, 65amp, 50amp, 20 amp breaker inside. They serve in order and distance: the house 100-130í , sub panel for a spa(not in use) 50-60í, sub panel for Rv hookup(30amp in use)100í, rv hookup (in use)50í.

The house has a panel where a 100amp breaker feeds the bus which has the stuff for the home. The only appliances that are electric are the washer/dryer, fridge, freezer, and the dishwasher everything else is gas.


Now to what I wanna do:

in the main service panel (electrician said it would be ok because of current wire gauge) I want to pull the 150amp breaker and replace it with a 200 or 225amp breaker. This is so I can upgrade the second panel to a 200 amp panel, I have a Siemens PW3040B1200CU to replace it with.

I then want to run power to a 30x30 barn 170í away. The old owner had a 75amp breaker in the current second panel feeding a sub panel in the barn, but the electrician I had inspect the electrical said the wire was not rated for it, and reduced it to 30amps. I have it pulled and disconnected because I want more power, so I dug up the old line, glad I did as it was not close to code (too shallow, broken conduit, no glue on the bells, hand torched sweeps, etc.)

Now my question is what size panel can I safely run in the barn from the second Siemens panel with the 200amp upgrade?

I want the maximum I can get there as I need power for welders, Kilns, lights, ventilation, etc. without overloading the whole system. Granted the barn will not be pulling it all at once all at one time. But one of my kilns pulls 50amps as an example, I usually run it at night


A friend of mine found me a overkill deal on wire to good to refuse, I was going to run 1/0-1/0-1/0-1 CU. But a construction friend got me a 250í spool of 250-250-250-2 AL XHHN-2 for $700 on close out. I know itís overkill since originally I only wanted about 100amps at the barn.

So the second question is again, what is the max panel I can run to the barn in that configuration?

The electrician I had was prohibitively expensive for all this work (wanted $3000 to pull and connect wires to another building only 40í away(May have power later if possible) and wanted me to do all the trench work And lay the conduit.
So I am doing the trenching, conduit, pulling, and mounting of the sub panels myself.

I was going to have a different electrician upgrade the 150amp breaker to 200amp, and make all the connections so they are all torqued properly since I donít have the tools. So I need to know what I need to buy panel wise for the barn. And any other things/arrangements I may need to have set up and ready for the electrician to connect it all, so I can save some money. (Yes conduit for barn will be oversized, and 24Ē + deep I have already dug 70% of the 170í by hand).


If you have made it through my novel Iím sorry and thank you, hopefully I can get some advice. I really want my workshop up and running, my equipment has been sitting a year now.
 
  #2  
Old 02-07-20, 04:57 AM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,283
Received 109 Votes on 101 Posts
You have two topics here:\

1. Voltage drop issues, combatted with heavier gauge wiring. I do not h ave the size/resistance/distance tables at my fingertips at ths moment to add more words here. Another, also expensive, solution is to have the power company install a pole more central in your complex and put the transformer, meter and service panel (main disconnect) there.

2. Total load. You might have been authorized only 150 amps with the power company. The "panel box" with the main disconnect and/or the meter box might be rated no more than 150 amps. Upgrading the service and service panel (with main disconnect) might require a separate permit.

All significant additions and upgrades need a load analysis. Sample rules are at the back of the NEC manual. For wire size you do two sets of calculations, one connected with heat that wires give off with appropriate upsizing for continuous vs. intermittent loadings, and the second for voltage drop without additional upsizing for continuous load. Use the larger of the two sizes.

You can do a separate load analysis for each building to help determine the feed wiring size and panel size for that building. If one building serves another building, be sure to include the load of the second building in the load of the first building.

You can futureproof with larger panels at (and yet heavier feed wiring to) the various buildings. Two hundred amp panels cost only a few dollars more than 100 amp panels, and nothing prohibits their installation where the feed is breakered for less.

The "branch circuit" breaker for the subject building in the upstream building panel has to protect the feed wiring for and the panel in the subject building and is therefore sized to take into account the ratings of these components.

When figuring voltage drop using raw figures including ohms per thousand feet, you use the round trip distance from panel to panel taking into account cable routing, not the distance from building to building. Some calculators want you to input the one way distance and do the math for you and this may cause confusion.
 

Last edited by AllanJ; 02-07-20 at 06:12 AM.
  #3  
Old 02-07-20, 11:31 PM
N
Member
Thread Starter
Join Date: Feb 2020
Posts: 5
Received 0 Votes on 0 Posts
Thanks, I guess I do have a crucial step in asking what my service is from the provider. The electrician that came out said the feed wire should be able to handle 225amps but the first master panel is only 200, but he was eyeballing the feeder to the 200amp main breaker in the panel he didnít open the meter side.

Moving everything is implausible, the power company here does not like over head utilities because of fire risk so all runs have to be underground from the poles. It would also involve adding two poles, and Moving all the wiring to a 48 in ground PV setup on the property which I donít think the solar company would be ok with doing.

I will call and ask about the main service amperage. The old owner had a 75 amp panel in the barn before and never had any issues, but half that may be luck because he was overloading the feeder wires, which were Maybe 4 gauge tinned copper (no markings), at 170í. I donít mind derating the new panel to the barn if I have too even with the large wires but would love to get as big as I can.
 
  #4  
Old 02-08-20, 07:15 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 13,799
Received 252 Votes on 220 Posts
Your main panel will dictate the largest-sized breaker you can have, in your case, 200 amps. If you want more than that you will need to replace the panel/meter. Your 3/0 copper should be adequate for a 200 amp feed to the next panel.

I doubt the barn had a 75 amp breaker as that is not a standard size. If there was that would be quite the oddball.

The largest feeder you can have running to the barn will depend on the size of the wire you use and what size breaker is allowed in the panel the circuit is originating from. Be sure to check your panel to make sure it is rated for a 200 amp breaker if that is what you want. I will note that there are thousands of homes in the US that have 100 amp services. I doubt you need 200 amps in the barn.
 

Last edited by Tolyn Ironhand; 02-08-20 at 07:37 AM.
  #5  
Old 02-08-20, 11:48 AM
N
Member
Thread Starter
Join Date: Feb 2020
Posts: 5
Received 0 Votes on 0 Posts
So the second panel is going to be replaced with the Siemens 200amp outdoor panel. And yes he had a 75 amp breaker feeding a 2 prong panel in the barn very odd indeed with no panel face or flash plate. But not surprising, the second panel when I bought the house was so clusterfked that the flash plate wouldnít install on it so everything was exposed. Thatís why I had an electrician out to pull everything, and clean it up for me because I didnít want my kids getting killed. But since I got the 250 kcmil AL for 700$ I was just going to use it to run to the barn from the 200 amp Siemens panel. Even if I canít run the 200amps the wire can handle, at least it future proof if I ever have money to get a serious transformer upgrade for bigger service down the line. I would like to preferably run at least a 150 amp panel in barn but if I can get away with 200 I would rather do that just because of future proofing. I only need max 100-120 amps at the barn for the rv and the kiln and doubt it will all ever be used at the same time.
 
  #6  
Old 02-08-20, 12:36 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 13,799
Received 252 Votes on 220 Posts
Can you post a picture of the 75 amp breaker?

The larger wire will be fine. The only issue you may have is fitting it under the lugs of the breaker(s)
 
  #7  
Old 02-09-20, 09:36 PM
N
Member
Thread Starter
Join Date: Feb 2020
Posts: 5
Received 0 Votes on 0 Posts
I have looked around for the breaker, and I think the electrician took all the ones he pulled out. I vaguely remember he may have asked for that one for his shop because he had never seen one. I looked at the photos of the panel in the inspection and they are too dirty, and low quality to see well. I thought i took photos of the panel before to send him but I canít find them in my files. Iíll just say itís been a year and looking online maybe it was a 70amp and I just canít remember. The second panel is currently an old crouse-hinds panel, that I do know. I am almost done with my trench though, so i will need to order the panel for the barn soon. I would really like to get the conduit and wire in the ground and pulled to the new J boxes. Iím itching to use my workshop I may just have to suck it up and pay an electrician to to the load calcs. I want to get it done sooner then later though, I just canít afford 1000ís of dollars for all the ground work and mounting.
 
  #8  
Old 02-10-20, 06:20 AM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,283
Received 109 Votes on 101 Posts
If you ran an extra heavy feeder for futureproofing and at one or both ends the wires don't fit into the panels or breakers that are not going to be replaced yet then you can terminate the new feeder in a junction box near the panel. Run not-so-fat wires, sized for the breaker in the feeding panel, the last few feet to the applicable panel.

Or you could make up the splices and not-so-fat jumpers (pigtails) in the applicable panel,but space may be at a premium.
 
  #9  
Old 02-10-20, 06:42 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 13,799
Received 252 Votes on 220 Posts
There are many load calculators online for free. IMO you likely don't need to bother with the wire size you are running and if you are installing 200 amp.
 
  #10  
Old 02-10-20, 09:20 AM
N
Member
Thread Starter
Join Date: Feb 2020
Posts: 5
Received 0 Votes on 0 Posts
So I checked my service and it is 200 amps and feeds the said Eaton Pv panel, the main breaker is a 200amp CSR 25K type breaker, the bus has a Eaton BR2150 breaker that feeds the current crouse-hinds second panel up the hill. So factoring wire being adequate for voltage drop, can the 150 be pulled replaced with a 200. Then can I replace the crouse-hinds with a Siemens 200amp panel with its own main breaker? Then from that panel I just need to figure out what to run to the barn. I am considering maybe running a 150 Siemens QN so wire size isnít an issue. Or can I run a 200 QN to the barn To another panel with a main breaker? Also what is the difference between a QN and a QNH breaker?
 
  #11  
Old 02-10-20, 10:47 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 13,799
Received 252 Votes on 220 Posts
So factoring wire being adequate for voltage drop, can the 150 be pulled replaced with a 200.
That is the 3/0 copper wire correct? If so it should be fine for 200 amps.

I am considering maybe running a 150 Siemens QN so wire size isn’t an issue. Or can I run a 200 QN to the barn To another panel with a main breaker?
Is that wire 250 MCM aluminum? If so that is good for 200 amps.

Also what is the difference between a QN and a QNH breaker?
I see no difference between the two. I would recommend contacting Siemens on that.

Note: I am not making any adjustments for voltage drop as I doubt it will be an issue.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: