Manual transfer switch planning

[m32825]

OP, can you help explain the 2 panels: distances from meter, loads, etc.

Does the garage really need to come off of the meter or could it be a sub to one of the 2 existing panels?
Could the second panel become a sub off of the first panel (even if it means upgrading first panel)?

Really need a load calc for each panel, what you consider critical loads, and of course what is planned for garage.

One panel is 30 feet from the meter and the other is about 75 feet. They are each central to about half of the house and everything fans out from them.

Will work on a load calculation for each panel and the garage. I see Mike Holt has a spreadsheet for residential load calculation, is that a good tool to use?

Not liking that ground wire seemingly so close.

May be the angle of the shot, there is at least 1.5" of distance between them.

I don't see any reason to upgrade this service unless the loads in your new building put you over 200A of actual load. Others seem to think that simply adding up breakers somehow equals load. It does not work that way, it is perfectly acceptable to have 3-400A worth of breakers on a 200A service as long as you have determined the load to be less than 200A. This is actually a common practice on much larger services.

Ah, thanks for explaining, that was a piece of info I was missing.

you need to separate out the circuits you want to run off generator
and make a generator fed panel whose load is sized to the generator.

I want the option to try and run anything. Priorities will change over the course of a day, there's not one set of loads sized to my generator that I see running. Additional breaker protection aside, the generator will drop the load to protect itself if it gets too high for it.

OP needs the loads calcs in order to provide enough info in order to understand best way to clean up this breaker mis-match and make gen tie-in easy. Current set-up is a problem.

Agree that we need more info. Will work on load calculations and get the poco to tell me what the existing service drop can supply to a meter base.

This just seems like a problem waiting to happen as the future loads change and no one is looking any further than just plugging in more cb's to the local panel.

Let's not put too much emphasis on that first picture I posted of how I wanted to lay things out. I should have started by stating what I want to do and let the process of "figuring out how to do it" play out. I want a solution that's good for the long haul and doesn't depend on the inspector missing something to pass.

What about a Meter Collar transfer switch from the Utility company to hook up your generator to the entire house?

Good suggestion and very convenient solution, but the poco doesn't allow them. I originally thought of the RV cable as a safe way to power a decent amount of the house from the generator, but it is capable of more than the 50A capacity of the cables/connectors. I've seen it sustain 60A@240V and would ultimately like to be able to get that to the house from a permanent pad. Until I figure out where the pad will be I was thinking the RV cable would be a good temporary solution.

-- Carl

 

[fastjohnny]

What about a service disconnect/feed through panel with an interlock? The 2 existing panels could be fed from that new panel, a generator inlet can feed an interlock breaker, and the feed through can go to the new garage panel.

https://www.amazon.com/dp/B004HIHMGG/?tag=atomicindus08-20

As for the inlet, consider this for greater than 50A generator:

http://www.nooutage.com/300134.htm

 

[wyliesdiesels]

Again his install is perfectly legal. My example was a 200A service nowhere did I mention a 200A main.

I agree he needs the service rated model which has a center off position rather than just Line or Auxillary.

You are right, it is legal per nec 230.90(A) exception 3 based upon calculated loads not exceeding se conductor rating (which would cover the meter pan).

This just seems like a problem waiting to happen as the future loads change and no one is looking any further than just plugging in more cb's to the local panel.

Except we cant make that determination WITHOUT knowing what the load calcs are.

For all we know there is no inspections in the OPs locale and some hack hooked this up...

Will work on a load calculation for each panel and the garage. I see Mike Holt has a spreadsheet for residential load calculation, is that a good tool to use?
-- Carl

YES!! Anything Mike Holt is excellent!!

What about a service disconnect/feed through panel with an interlock? The 2 existing panels could be fed from that new panel, a generator inlet can feed an interlock breaker, and the feed through can go to the new garage panel.

https://www.amazon.com/dp/B004HIHMGG/?tag=atomicindus08-20

As for the inlet, consider this for greater than 50A generator:

http://www.nooutage.com/300134.htm

While possible, it may be a PITA as the (2) 150a breaker panels would need to be converted to subpanels(unbond neutrals, add ground bars).....

 

[mm08822]

Except we cant make that determination WITHOUT knowing what the load calcs are.

For all we know there is no inspections in the OPs locale and some hack hooked this up...



YES!! Anything Mike Holt is excellent!!



While possible, it may be a PITA as the (2) 150a breaker panels would need to be converted to subpanels(unbond neutrals, add ground bars).....

I was saying Bert was right in what he stated as I found the exception in the code. The OP's situation is still TBD. Still think that is a bad practice for residential - industrial/commercial setting more appropriate as there are hopefully more watchful eyes on this otherwise unmonitored exception.

I have a better idea for those 150A disco's - shitcan them.

 

[mm08822]

OP, if your load calcs (with the garage) put you under 200A then:

I would get rid of the the two 150A discos and the trough.
Hang a Siemens PW1224B1200CU (or SW2040B1200 $170 @ depot) panel to the left of the meter fed through a 2” ****** w/ 2/0 Cu.
Add a 2P 50A cb (Q250 = $11) in the new panel interlocked with Siemens# ECSBPK03 Interlock kit
Feed the 50A cb with a 50A PIB located below the new panel
Add 2 2P 125A cb (Q2125P = $60 x 2) in the new panel (Verify wire size of feeders – look like only 1/0 Cu clad Al – good for only 120A)
Run the existing conduits into the new panel and pick-up the 2 existing sub panels (Looks like 4 wire)
Add a 2p 100A (Q2100 = $42) (or whatever size you’re planning) and feed the garage with a conduit out the bottom of the new panel.
Add 2 grd rods and connect with #6 Cu, bond h2o and across hw heater.
You will have 4 empty cb spaces remaining.

https://www.downloads.siemens.com/d...aspx?pos=download&fct=getasset&id1=BTLV_39296
https://www.downloads.siemens.com/d...aspx?pos=download&fct=getasset&id1=BTLV_39445
https://www.downloads.siemens.com/d...aspx?pos=download&fct=getasset&id1=BTLV_39383
https://www.downloads.siemens.com/d...aspx?pos=download&fct=getasset&id1=BTLV_47493

If you are over 200a load then increase meter and get a bigger panel.
If you don’t like Siemens then pick your own flavor and do similar.

 

[wyliesdiesels]

I was saying Bert was right in what he stated as I found the exception in the code. The OP's situation is still TBD. Still think that is a bad practice for residential - industrial/commercial setting more appropriate as there are hopefully more watchful eyes on this otherwise unmonitored exception.

I have a better idea for those 150A disco's - shitcan them.

agreed. its a lousy setup.

Why didnt they just do a small main breaker panel with 2 disconnects?

 

[m32825]

OP here, really appreciate the help, guys...

What about a service disconnect/feed through panel with an interlock? The 2 existing panels could be fed from that new panel, a generator inlet can feed an interlock breaker, and the feed through can go to the new garage panel.

https://www.amazon.com/dp/B004HIHMGG/?tag=atomicindus08-20

As for the inlet, consider this for greater than 50A generator:

http://www.nooutage.com/300134.htm

I'm liking the interlock approach. Thanks for the greater than 50A plug suggestion, I havent seen those before.

I have a better idea for those 150A disco's - shitcan them.

Yeah, I'm on board with that.

OP, if your load calcs (with the garage) put you under 200A then...

Thank you so much for the specifics, it really helps me picture the solution!

YES!! Anything Mike Holt is excellent!!

Great, I am working on the load calculation but it will probably be the weekend to wrap it up. I am thinking I need to do one for each panel, then combine for the service. Is that the right idea?

-- Carl

 

[wyliesdiesels]

Great, I am working on the load calculation but it will probably be the weekend to wrap it up. I am thinking I need to do one for each panel, then combine for the service. Is that the right idea?

-- Carl

You could do it like that but not as important as the total load on the pan.

I doubt either one of those panels is over 150a load.

 

[mm08822]

Quote:
Originally Posted by m32825 View Post
Great, I am working on the load calculation but it will probably be the weekend to wrap it up. I am thinking I need to do one for each panel, then combine for the service. Is that the right idea?

-- Carl
You could do it like that but not as important as the total load on the pan.

I doubt either one of those panels is over 150a load.
*****************
Each sub panel has a feeder that needs to be checked for load and the size of feeders looks to be only 1/0 Cu clad Al – good for only 120A not 150A. OP needs to verify each of those feeder sizes.
Also put numbers in for the garage for the overall service load calcs.

Also my choice of the 50A cb and PIB was based on your initial request. If you want to go higher you can with the proposed arrangement.

 

[wyliesdiesels]

Each sub panel has a feeder that needs to be checked for load and the size of feeders looks to be only 1/0 Cu clad Al – good for only 120A not 150A. OP needs to verify each of those feeder sizes.
Also put numbers in for the garage for the overall service load calcs.

Also my choice of the 50A cb and PIB was based on your initial request. If you want to go higher you can with the proposed arrangement.

Huh?

Where did anyone say the feeders are CCA?

The OP has said several times its 1/0 CU and looking at the ends of the wire in the pan lug, looks like solid copper to me.

1/0 CU is good for 150a 75* column.

Im really lost here....

 

[mm08822]

Huh?

Where did anyone say the feeders are CCA?

The OP has said several times its 1/0 CU and looking at the ends of the wire in the pan lug, looks like solid copper to me.

1/0 CU is good for 150a 75* column.

Im really lost here....

Look hard at the pic of the 150a disco. Load side of that disco looks like 1/0 CCA that feeds each subpanel.

 

[wyliesdiesels]

Look hard at the pic of the 150a disco. Load side of that disco looks like 1/0 CCA that feeds each subpanel.

Ok were talking about different things here.

I was thinking of the 1/0 CU between meter and discos which is what the previous topic was about as far as overloading the wire in the trough.

And now I see what youre talking about. The AL SER between disco and sub....

There is no size markings on the AL SER.

OP can you open a subpanel and see if there is a size marking on the feeder in there?

 

[mm08822]

Ok were talking about different things here.

I was thinking of the 1/0 CU between meter and discos which is what the previous topic was about as far as overloading the wire in the trough.

And now I see what youre talking about. The AL SER between disco and sub....

There is no size markings on the AL SER.

OP can you open a subpanel and see if there is a size marking on the feeder in there?

Yeah, I'm moving on - IMO, the discos are history and so are their feeders from the meter.

In the OP's current setup, the discos are the main panel and each panel within the house are sub-panels.

I looked at the diameter of the line side conductors and compared it to the load side diameter - looks same to me. Then I saw CCA on load side at lug.

 

[m32825]

OP can you open a subpanel and see if there is a size marking on the feeder in there?

Checked this morning, no labels on the wires there either. The subpanel supply wires look the same size as the copper ones from the meter base. I did see that the inside panel is rated for 150A max.

-- Carl

 

[fastjohnny]

I'm liking the interlock approach. Thanks for the greater than 50A plug suggestion, I havent seen those before.



-- Carl

Don't spend your money on that though, build your own with Anderson 175A plugs readily available.

 

[m32825]

Don't spend your money on that though, build your own with Anderson 175A plugs readily available.

Thanks, will keep that option in mind. Do the Anderson connectors create a weatherproof connection, or is there another layer of protection for that?

-- Carl

 

[m32825]

OP here, back from doing some of my homework...

I used the Residential Load Calulation spreadsheet from Mike Holt's site and came up with just over 200A demand load and 100A neutral demand. Seems like I'm going to need to upgrade the meter base to add power for the garage. Working on finding out from the poco how much current the existing service can supply.

-- Carl

 

[mm08822]

OP here, back from doing some of my homework...

I used the Residential Load Calulation spreadsheet from Mike Holt's site and came up with just over 200A demand load and 100A neutral demand. Seems like I'm going to need to upgrade the meter base to add power for the garage. Working on finding out from the poco how much current the existing service can supply.

-- Carl

Mind posting your ss?
Have you ever taken load readings during your heaviest usage?

 

[fastjohnny]

Thanks, will keep that option in mind. Do the Anderson connectors create a weatherproof connection, or is there another layer of protection for that?

-- Carl

I wouldn't say it is completely sealed, but plenty enough. I also use them for plow power plugs, jumper cables, etc, plenty places exposed to moisture without incident.

For my gen inlet, I mounted them in the bottom of my surface mount panel so the inlet plugs upward.

 

[wyliesdiesels]

Mind posting your ss?
Have you ever taken load readings during your heaviest usage?

Yeah his load calcs are pretty high.

Either something was inputted wrong or his bills are through the roof.

 

[mm08822]

I wouldn't say it is completely sealed, but plenty enough. I also use them for plow power plugs, jumper cables, etc, plenty places exposed to moisture without incident.

For my gen inlet, I mounted them in the bottom of my surface mount panel so the inlet plugs upward.

I have used Anderson connectors before of lower amperage and they are a little sketchy. I've seem them in use on forklift batteries, manlifts and chargers and battery banks. The latest was with robotics for the high school kids.

You must have the proper crimper ($$), high strand flexible conductors and the proper placement of the connector on the conductor. Without proper placement, the connector tends to rotate and can even not make contact with the mate. (learned that one the hard way.)
These are also best suited for lower voltages that use individual conductors. OP would need a cable assembly for proper conductor protection. Also these connectors are not finger safe. I would save these for dc applications.

 

[m32825]

Mind posting your ss?
Have you ever taken load readings during your heaviest usage?

See attached. I studied a little more and adjusted it, that improved things but I still feel like a monkey just moving levers at random and getting excited when things change...

I've got a Fluke clamp and a cheaper Harbor Freight clamp with peak hold. I've been using them with a straight 240V load on the generator, but haven't looked at any of the house wiring with them. I have decent access to the wires in the cable trough, how do you measure to get an idea of the combined 120/240 loads?

-- Carl

 

[m32825]

Yeah his load calcs are pretty high.

Either something was inputted wrong or his bills are through the roof.

Would not be surprised to see us hit $600 for August, that's our highest month of the year. The house is occupied 24/7, so we never get a chance to "turn the thermostat up while we're away". Six occupants worth of cooking and cleaning, and plenty of freezer/fridge storage for fresh food and bulk meat purchases, it all adds up. Is that "through the roof"?

-- Carl

 

[m32825]

OP here, more homework results...

Clamped both hots on the supply side of the meter and observed for a hour this evening. Most of the time the highest reading was in the 40A to 70A range, the peak was 85A for less than a minute. Both AC units were running, dryer was on, cooking in the kitchen, and the well pump came on.

-- Carl

 

[fastjohnny]

I have used Anderson connectors before of lower amperage and they are a little sketchy. I've seem them in use on forklift batteries, manlifts and chargers and battery banks. The latest was with robotics for the high school kids.

You must have the proper crimper ($$), high strand flexible conductors and the proper placement of the connector on the conductor. Without proper placement, the connector tends to rotate and can even not make contact with the mate. (learned that one the hard way.)
These are also best suited for lower voltages that use individual conductors. OP would need a cable assembly for proper conductor protection. Also these connectors are not finger safe. I would save these for dc applications.

Anything not properly assembled becomes sketchy, point taken with risk for improper use. I utilize #1 welding cable, heat shrink after crimping, and have no problems in dozens of assemblies in use from DC applications drawing to 200A to 240V AC/DC

 

[mm08822]

OP here, more homework results...

Clamped both hots on the supply side of the meter and observed for a hour this evening. Most of the time the highest reading was in the 40A to 70A range, the peak was 85A for less than a minute. Both AC units were running, dryer was on, cooking in the kitchen, and the well pump came on.

-- Carl

A few points noted from your Mike Holt Load calc sheet:
1) Number of small appliance ckts – do you really have more than 2?
2) Number of laundry ckts – do you really have more than 1?
3) What and where are the loads for the garage?

This form is capable of two calculation methods (checkbox at top left next to page title):
1) Standard calculation - for entirely new construction = 46,491 va. (Method that you used.)
2) Optional calculation - NEC article 220.80 lets you calculate in a simpler, more conservative manner for existing structures = 39,300 va. (This is very close to the former NEC method used in residential calculations. See attached example.)

View attachment ResidentialLoadCalculations (3A)_MM.pdf

Your heat pumps and the other large appliances are driving the size of the calculated service required. Everything else is insignificant. Meanwhile, you only read ~70A from the service with many of the large appliances running. I would suggest you take a few more readings - different (hot) days, turn on worst case scenario loads and read the values – document the running loads, readings, outside temp and timestamps. A peak-hold meter would be great to use.

Unless your garage has some large, sustained loads, you should be fine with the existing 200A service/meter pan.
What do you plan to do in the garage? Garage size? Loads?

 

[m32825]

Wow, I really appreciate the detailed feedback!

A few points noted from your Mike Holt Load calc sheet:
1) Number of small appliance ckts – do you really have more than 2?
2) Number of laundry ckts – do you really have more than 1?
3) What and where are the loads for the garage?

I was trying to figure out the existing load before adding stuff on. We are working towards splitting the house for parents on one end, rest of us on the other. So I need to add that load as well, working on it...

This form is capable of two calculation methods (checkbox at top left next to page title):
1) Standard calculation - for entirely new construction = 46,491 va. (Method that you used.)
2) Optional calculation - NEC article 220.80 lets you calculate in a simpler, more conservative manner for existing structures = 39,300 va. (This is very close to the former NEC method used in residential calculations. See attached example.)

Aha, I had tried the optional calculation but my demand was going to zero. It sure helps to have an example from someone who knows what they're doing!

Your heat pumps and the other large appliances are driving the size of the calculated service required. Everything else is insignificant. Meanwhile, you only read ~70A from the service with many of the large appliances running. I would suggest you take a few more readings - different (hot) days, turn on worst case scenario loads and read the values – document the running loads, readings, outside temp and timestamps. A peak-hold meter would be great to use.

I'll do some more logging this weekend. I tried the peak hold on my cheap Harbor Freight meter but I'm not sure how much I trust it. Seems to keep gradually climbing. Maybe something is pulsing, like a cook top? I did see it lock in peaks of 140A when the AC units kicked on.

Unless your garage has some large, sustained loads, you should be fine with the existing 200A service/meter pan.
What do you plan to do in the garage? Garage size? Loads?

It's a 30x50 detached garage. Nothing industrial, like multiple machines operated at the same time. I have a generator/welder that I'd like to switch for a plug-in welder, need 50A@240 for that. Need to be able to run a heavy duty angle grinder, drill press, belt sander, metal chop saw, big shop fan, Liftmaster garage door opener, and maybe 2KW worth of indoor/outdoor lighting.

-- Carl

 

[m32825]

OP here with results of homework...

I revisited the residential load calculation using the optional calculation method. I refined a few of the numbers, heater strips and well pump are bigger than what I thought initially. Then I doubled up on things to support dividing the house into two dwelling areas (i.e. two kitchens, two laundry areas, etc) to take into account what we plan to do from a remodeling perspective: aging parents on one end, my family unit on the other.

Before adding the garage loads I'm interested to know what these results mean for the existing infrastructure. Will we need to run larger conductors from the disconnects to the subpanels?

Where do I add the garage loads to the spreadsheet? Thanks!

-- Carl