200 vs 300 amp service

[bugman53]

Replacing a meter base is almost guaranteed to be more exoensive than a 4th conductor.

lets run the numbers on a 125 foot run (what i did for my shop) $953 for a 100 amp subpanel or $574 for a 200 amp main panel with a "400"amp meter base.

The 200 amp run came in cheaper by $379!


To run 2 gauge THWN wire for a 100 amp sub panel. each wire is 1.50 a foot at lows. that is 6.00 per foot for wire,

Wire $750
100 amp subpannel 76.04
Conduit 6.84 x (125/10) $88
Breaker $39

So 953.04 For a 100 amp subpannel.

For a 200 amp run

4/0 Underground cable 2.16 a foot, $270

400 amp meter base less than $200.

Main panel $89

A couple LB's and 20 foot of conduit $15


Or $574 for a 200 amp sub pannel with a 400 meter base.
Install was free as i pulled a permit and did it myself.


You could save some money by running you THWN wire in conduit to an outside junction box and transition to 1/0 aluminum underground wire. Then you have the cost of a junction box, special aluminum to copper lugs.

Either way when you run the numbers and take into account what has to be done to be NEC compliant upgrading the meter base can be cheaper with more amprage.

 

[alfredeneuman]

What wire size did you run to those bad boys?

Some were already in place and we only added circuits to them. I didn't pay attention to the feed's wire size.
The ones we installed were relatively easy. Just extended the stand up section of the main service and bolted factory bent busses to them.
Just take the exact info off the service, order it as a unit panel and all, and wait a few weeks for delivery.
The kits had everything you needed to do the job except the tools.

 

[wyliesdiesels]

No code prevents it the main panel in most homes is your limiting factor. The breaker size and buss bar ampacity limit.

Most of your common home main load centers have a max breaker size of 100 or 125 amps. There are ways to get around this (feed through lugs although some still have an ampacity limint) but you will come out much cheaper to just do a dual lug meter base and install a second main panel on your shop if you need more than 100amps you are probably pushing a 200 amp service anyway.

The cost savings of the wire alone to run 3 v 4 conductor wire is a big advantage to a second main panel.

Then why did you say subpanels are limited to 100a?

 

[bugman53]

Then why did you say subpanels are limited to 100a?

If your main panel is only rated by the manufacture for a 100amp breaker or lugs then you are limited to a 100amp sub panel just like i said.

 

[alfredeneuman]

Lots of residential grade panels have a 125 amp maximum branch breaker rating.

 

[mike93lx]

There is no winning this argument

 

[sberry]

Ain't no mystery about price here either, one has copper wire.

 

[bugman53]

Ain't no mystery about price here either, one has copper wire.

Calculations for 125 foot 100 and 125 amp subpanel with all aluminum wire and transition to URD.

Breaker $39
Aluminum SER (service entrance cable) 15 foot (might be more depending on where you main panel is) 2.34 x 15 $35.10 (3/0 2.95 x 15 $44.25 Edit $146.25 )
(SER is derated to use 60*C ampacity when used as a feeder)
Nema 3R junction box 71.31
1/0 URD 4 conductor 1.70 Foot $212.5 (3/0 required for 125 amps) 2.67 a foot 333.75)
Lugs to connect SER to URD rated for aluminum wire 18.00 Each $72
Sub panel 76.04

Grand total 100 amp subpanel $505.95
Grand total 125 amp subpanel $636.35 (edit $738)
Grand total for 200 amp main panel $574
Grand total for 100 amp Main Panel off meter base $469

Like I said Run the numbers and you will be surprised. It would cost MORE to install a 125 amp subpanel in this case than a 200 amp panel.

 

[jkeyser14]

You will never use the full 100 amps out in the shop unless you are running everything all at the same time. Never happen in a one man shop.
I have all of the equipment you mentioned above and then some and have never popped a breaker either in the shop panel our the house panel. That's 35 years of use out of a 200 amp service on the house with 100 pulled to the shop.
200 amp panel in the house will be fine.
Mark

I would rethink that. My Tesla pulls 40A, my wofe when she gets hers will also pull 40A. My welder pulls 50A. It is easy to use 100A in a garage

 

[Showkey]

There is no winning this argument

With this section it entertaining and we learn a few things from time to time........but........ the contributors can’t agree on what day it is

 

[bugman53]

Calculations for 125 foot 100 and 125 amp subpanel with all aluminum wire and transition to URD.

Breaker $39
Aluminum SER (service entrance cable) 15 foot (might be more depending on where you main panel is) 2.34 x 15 $35.10 (3/0 2.95 x 15 $44.25)
(SER is derated to use 60*C ampacity when used as a feeder)
Nema 3R junction box 71.31
1/0 URD 4 conductor 1.70 Foot $212.5 (3/0 required for 125 amps) 2.67 a foot 333.75)
Lugs to connect SER to URD rated for aluminum wire 18.00 Each $72
Sub panel 76.04

Grand total 100 amp subpanel $505.95
Grand total 125 amp subpanel $636.35
Grand total for 200 amp main panel $574
Grand total for 100 amp Main Panel off meter base $469

Like I said Run the numbers and you will be surprised. It would cost MORE to install a 125 amp subpanel in this case than a 200 amp panel.

Edit I just looked up the max wire size for a 125 amp GE beaker and it is 2/0 So you can NOT do aluminum SER cable for the 125 amp panel, It has to be copper at 9.75 a foot this brings the 125 amp sub panel to 738. Keep in mind you need 5.5" of space for the min bend radius assuming you panel has this much room between the lugs and the side of the panel.

 

[bugman53]

Replacing a meter base is almost guaranteed to be more exoensive than a 4th conductor.

Another option with an existing meter base, There are add on lug kits for some 200 amp meter bases that will allow you to pull 100amps. This gets you to 3 conductors and you are starting outside so you can use URD cable without the transition.

 

[bugman53]

To the Original Post,

I would recommend either installing a dual lug 200 amp meter base or a 400 amp meter base or run you garage to that, Simple, Cheap, Gets you all the amperage you need, does not take up space in your main house panel.

Since this is a new house anyway the cost would not be much difference and you can run 200 amps to your shop if you need.

 

[alfredeneuman]

(SER is derated to use 60*C ampacity when used as a feeder)

Would you care to cite a Code reference for that? (Hint: There isn't one).
You could conceivably use 1/0 for it because in the 75C column it's rated for 120Amps, and is not a standard breaker rating.
All circuit breakers have lugs suitable for the wire size. Otherwise they wouldn't have a UL listing.

 

[bugman53]

Would you care to cite a Code reference for that? (Hint: There isn't one).
You could conceivably use 1/0 for it because in the 75C column it's rated for 120Amps, and is not a standard breaker rating.
All circuit breakers have lugs suitable for the wire size. Otherwise they wouldn't have a UL listing.

338.10(B)(4) Installation Methods for Branch Circuits and Feeders.

(a) Interior Installations. In addition to the provisions of this article, Type SE service-entrance cable used for interior wiring shall comply with the installation requirements of Part II of Article 334, excluding 334.80.

Where installed in thermal insulation the ampacity shall be in accordance with the 60°C (140°F) conductor temperature rating. The maximum conductor temperature rating shall be permitted to be used for ampacity adjustment and correction purposes, if the final derated ampacity does not exceed that for a 60°C (140°F) rated conductor.

SER cable has have a half of dozen revisions over the last 20 years about how it is supposed to be rated. I am no expert by any means on this but also the Lugs AND the equipment have to be rated for 90* or you have to use the 60* column for a branch circuit.

It seems like at first glance you can use the higher rated table but when you dig into it there always seems to be something that drops you down to the 60* table. Pretty much it comes down to the equipment has to be rated to 90*c and even if the lugs are its hard to prove to an inspector you Main panel is rated for 90* connections.

From what i understand Just use the 60* table on all branch circuits to be sure you are code complaint.

 

[bugman53]

Would you care to cite a Code reference for that? (Hint: There isn't one).
You could conceivably use 1/0 for it because in the 75C column it's rated for 120Amps, and is not a standard breaker rating.
All circuit breakers have lugs suitable for the wire size. Otherwise they wouldn't have a UL listing.

The circuit Breaker might have lugs suited for Copper at the rated ampacity but if you have to up size your wire to run aluminum then you can get into trouble.

IE a 125 AMP breaker, 2/0 Wire connections, you have to use the 60* table for ampacity for what ever reason, You would need 3/0 wire and it will not fit the breaker, But with copper you can run smaller wire and be fine.

 

[alfredeneuman]

Where installed in thermal insulation the ampacity shall be in accordance with the 60°C (140°F) conductor temperature rating. The maximum conductor temperature rating shall be permitted to be used for ampacity adjustment and correction purposes, if the final derated ampacity does not exceed that for a 60°C (140°F) rated conductor.

 

[bugman53]

Where installed in thermal insulation the ampacity shall be in accordance with the 60°C (140°F) conductor temperature rating. The maximum conductor temperature rating shall be permitted to be used for ampacity adjustment and correction purposes, if the final derated ampacity does not exceed that for a 60°C (140°F) rated conductor.

Is there not insulation in you exterior walls? It does not state that the entire run has to be insulated. If your run comes up the inside of an exterior wall and then to an outside junction box then that is installed in thermal insulation the way i read it. But that is a call for your electrical inspector

Also all equipment has to be rated for the higher temperature rating. You have to show all equipment, breakers, and lugs are rated to the 75* or 90* C to use them.

Once again not impossible but it is best to use the 60* table to size your wire unless your electrical inspector says it is ok. Its that one little thing like above that if you Inspector wants to push the point he could fail you.

It is still a mute point as even if you can use the 75* table and use smaller SER cable and stay with aluminum the whole run. You are still fighting to get 125 amps or you can just put in a dual lug meter base and get 200 amps for similar or less cost.

 

[alfredeneuman]

Is there not insulation in you exterior walls?
Also all equipment has to be rated for the higher temperature rating. You have to show all equipment, breakers, and lugs are rated to the 75* to use them.

No insulation in my exterior walls. I live in SoCA in a place that predates the requirement.
There a no lugs on breakers listed to 90*, all modern are 75, some older ones were rated @60 (Zinsco comes to mind).

A certain amount of SE has to be in insulation to drop the conductor rating.
10' continuous? or >10% of the entire run. It doesn't automatically come into play if it even touches insulation.

You go ahead and do things the way you wish they were.

 

[bugman53]

Where installed in thermal insulation the ampacity shall be in accordance with the 60°C (140°F) conductor temperature rating. The maximum conductor temperature rating shall be permitted to be used for ampacity adjustment and correction purposes, if the final derated ampacity does not exceed that for a 60°C (140°F) rated conductor.

Apparently to follow up even more , I appears you do have to de rate SE cable to 60* (same as NM type cable). Even if not in insulation.

7-88 Log #2639 NEC-P07 Final Action: Accept
(338.10(B)(4)(a))
__________________________________________________ __________
Submitter: James M. Daly, General Cable

Recommendation: Delete the phrase �excluding 334.80� and change the
comma after �Article 334� to a period.

Substantiation: When Type SE conductors are used for interior wiring, as a
replacement for Type NM cable, the ampacity of the conductors should be the
same as permitted for NM cable since the insulations used are the same both
NM and SE conductors.

Panel Meeting Action: Accept

Panel Statement: This action will modify the action taken on Proposal 7-84.

Number Eligible to Vote: 14

Ballot Results: Affirmative: 14
____________________________________

 

[wyliesdiesels]

Someone has reading comprehension issues

 

[alfredeneuman]

Substantiation: When Type SE conductors are used for interior wiring, as a
replacement for Type NM cable, the ampacity of the conductors should be the
same as permitted for NM cable since the insulations used are the same both
NM and SE conductors.

I'm not aware of any NM cable of a size larger than #2.
Why don't you try to find some since you posted the substantiation?

 

[bugman53]

I'm not aware of any NM cable of a size larger than #2.
Why don't you try to find some since you posted the substantiation?

Why don't you go here and hash it out with theses guys that seem to live and breath electrical code. They seem to share the opinion that you have to use the 60* rating when using SER on a branch circuit.

https://forums.mikeholt.com/showthread.php?t=94744

Either way unless you live in an old house with no insulation in Southern California or do some tricky cable runs you are probably going to be stuck using the 60* column from what i understand.

You mileage may vary. either way 60* or 75* has no bearing on the Point of this thread or what i did with my shop and recommend to the OP. 200 amp main panel is still better is than a Whatever ampacity sub panel in a lot of cases.

So once again what is the point to argue over 60 v75 degree Celsius on SER rating when either way a Dual lug meter base wins out in cost(sometimes), ampacity and space in your main panel?

 

[bugman53]

PS. The NEC changes there mind every few years on what you can rate SER cable to so what is applicable today might not apply tomorrow or last year.

I would recommend calling you local electrical inspector and ask before running any cable. What ever he says go with.

 

[wyliesdiesels]

PS. The NEC changes there mind every few years on what you can rate SER cable to so what is applicable today might not apply tomorrow or last year.

I would recommend calling you local electrical inspector and ask before running any cable. What ever he says go with.

aww no thats not how it works...

 

[mm08822]

Apparently to follow up even more , I appears you do have to de rate SE cable to 60* (same as NM type cable). Even if not in insulation.

7-88 Log #2639 NEC-P07 Final Action: Accept
(338.10(B)(4)(a))
__________________________________________________ __________
Submitter: James M. Daly, General Cable

Recommendation: Delete the phrase �excluding 334.80� and change the
comma after �Article 334� to a period.

Substantiation: When Type SE conductors are used for interior wiring, as a
replacement for Type NM cable, the ampacity of the conductors should be the
same as permitted for NM cable since the insulations used are the same both
NM and SE conductors.

Panel Meeting Action: Accept

Panel Statement: This action will modify the action taken on Proposal 7-84.

Number Eligible to Vote: 14

Ballot Results: Affirmative: 14
____________________________________

Why don't you go here and hash it out with theses guys that seem to live and breath electrical code. They seem to share the opinion that you have to use the 60* rating when using SER on a branch circuit.

https://forums.mikeholt.com/showthread.php?t=94744

Either way unless you live in an old house with no insulation in Southern California or do some tricky cable runs you are probably going to be stuck using the 60* column from what i understand.

You mileage may vary. either way 60* or 75* has no bearing on the Point of this thread or what i did with my shop and recommend to the OP. 200 amp main panel is still better is than a Whatever ampacity sub panel in a lot of cases.

So once again what is the point to argue over 60 v75 degree Celsius on SER rating when either way a Dual lug meter base wins out in cost(sometimes), ampacity and space in your main panel?

This is from the 2008 code input.

OP is on the 2014 Code.

The Mike Holt thread you mention is from 2008. Again, OP is 2 code cycles past that.

FYI - Mike Holt forum has many people posting on it. Not all replies/comments are correct. Mods don't validate each reply. That forum only carries the name of Mike Holt. It is not his opinion/responses being posted. (I am by no means slamming it and have found some very good perspectives on various topics, but everything from the internet has to be checked. In this case - taken out of context - Op is on 2014 NEC. Requirements have changed.))


The 2014 code for SE cable - 338.10 (4) (A) excludes the reference to derate SE ampacity to the 60C ratings. Use the ratings of the SE conductor insulation - typically xhhw-2 = 75C.

 

[alfredeneuman]

I became a member of the Holt Forum over 15 years ago.
You first brought up the 60* vs 75* issue.
I expected that you would "put your money where your mouth is" so to speak, but failed to do so.
(I'm still waiting on the NM over size 2 thing)

 

[mm08822]

Your point is noted about gaining more installed capacity for the buck. Since OP has not installed his hardware yet, now is the time to consider the options of cost vs. benefit. If he can get a 200a service for the same cost as 90/100/125a sub panel, then go for it.

Your cost comparisons below are a little skewed however.

lets run the numbers on a 125 foot run (what i did for my shop) $953 for a 100 amp subpanel or $574 for a 200 amp main panel with a "400"amp meter base.

The 200 amp run came in cheaper by $379!


To run 2 gauge THWN wire for a 100 amp sub panel. each wire is 1.50 a foot at lows. that is 6.00 per foot for wire,

Why run CU when AL can be run?
Why run all same size conductors? Neutral and ground can be reduced.

Wire $750
100 amp subpannel 76.04
Conduit 6.84 x (125/10) $88
Breaker $39

So 953.04 For a 100 amp subpannel.

For a 200 amp run

4/0 Underground cable 2.16 a foot, $270

Missing the exterior j-box and splicing costs to transition from use to thwn or xhhw to enter the building.

In the above example you run conduit point-point and here you only provide for exiting the ground?


400 amp meter base less than $200.

Main panel $89

A couple LB's and 20 foot of conduit $15 2 lengths of 2" pvc conduit is $15.


Or $574 for a 200 amp sub pannel with a 400 meter base.
Install was free as i pulled a permit and did it myself.


You could save some money by running you THWN wire in conduit to an outside junction box and transition to 1/0 aluminum underground wire. Then you have the cost of a junction box, special aluminum to copper lugs.

Either way when you run the numbers and take into account what has to be done to be NEC compliant upgrading the meter base can be cheaper with more amprage.

Calculations for 125 foot 100 and 125 amp subpanel with all aluminum wire and transition to URD.

Breaker $39
Aluminum SER (service entrance cable) 15 foot (might be more depending on where you main panel is) 2.34 x 15 $35.10 (3/0 2.95 x 15 $44.25 Edit $146.25 )
(SER is derated to use 60*C ampacity when used as a feeder)
Nema 3R junction box 71.31
1/0 URD 4 conductor 1.70 Foot $212.5 (3/0 required for 125 amps) 2.67 a foot 333.75)

2/0 AL is rated for 115A if 60C were used.
No need to jump to 3/0 and 2/0 AL even covers the vd at 125'.
115A can be protected @125A since it appears the loads will never be close to 115.A

Lugs to connect SER to URD rated for aluminum wire 18.00 Each $72
Sub panel 76.04

Grand total 100 amp subpanel $505.95
Grand total 125 amp subpanel $636.35 (edit $738)
Another option - conduit point - point with all xhhw AL, no j boxes, splices, provides feeder protection.
Grand total for 200 amp main panel $574
Grand total for 100 amp Main Panel off meter base $469

Like I said Run the numbers and you will be surprised. It would cost MORE to install a 125 amp subpanel in this case than a 200 amp panel.

 

[bugman53]

Your point is noted about gaining more installed capacity for the buck. Since OP has not installed his hardware yet, now is the time to consider the options of cost vs. benefit. If he can get a 200a service for the same cost as 90/100/125a sub panel, then go for it.

Your cost comparisons below are a little skewed however.

Great points, It has been awhile since i have messed with this stuff i am sure i missed a few things.


That was a a big cost savings, since the meter base was outside i could run URD directly to the meter base. On my shop the main panel is on an outside wall, I called the inspector and he said as long as you come up the side of the building with conduit and Do an LB directly into the back of the panel He was OK with out a junction box and SER. This let me run URD Meter base to panel. I have heard that some inspectors will not allow this, He was under in impression that since it never enters the building except into the main panel it is not considers inside.

If your meter base (or your inspector says no) is on an interior wall you are correct with both if you run URD you will have to do a transition at your shop to a wire that is approved for inside runs.

I ran the conduit out of each building to 36" deep and the run is direct buried the rest of the way. on The THWN it has to be in conduit not direct burial correct?


Great points with the Aluminum THWN and reduced size neutral. I think i ran "mammoth" 4/0 4/0 4/0 but it might have been "sweetbrier" with a 2/0 neutral, We ran a load calculation and i forgot what wire we settled on.

I am not very familiar with XHHW wire. Is that not the heavy plastic insulated stuff that is in SER cable?

 

[bugman53]

I became a member of the Holt Forum over 15 years ago.
You first brought up the 60* vs 75* issue.
I expected that you would "put your money where your mouth is" so to speak, but failed to do so.
(I'm still waiting on the NM over size 2 thing)

Like i said multiple times, The code changes be sure you can use the 75* table or call your local inspector since he is going to be the one signing off on it.

You are the only one here that has mentioned anything about NM over 2 gauge? Let us know when you figure it out.

Sounds to me that you just like to argue about things unrelated to the Original post.

 

[volleyball]

I got lost with all the ideas.
For the OP, I'd go with 200A service. Where I would change up is running 2 sub feeds to the out building. ! for the shop, 1 for the dwelling.
That way you could meter the dwelling if need arose.
If future things change and you need more power such as multiple EV's you could upgrade the main panel or split power

 

[wyliesdiesels]

Like i said multiple times, The code changes be sure you can use the 75* table or call your local inspector since he is going to be the one signing off on it.

You are the only one here that has mentioned anything about NM over 2 gauge? Let us know when you figure it out.

Sounds to me that you just like to argue about things unrelated to the Original post.

you completely missed his point about that. go back and read it a few times

 

[Lassen Forge]

It used to be a 50 amp service for everyone, but that was back in the 1930's, when your whole home was run on 4 screw in fuses, and one cartridge 50 amp...

The more power you can get, the better you are so I would say 300A MINIMUM. If you can score 3 phase then do it, because it's a boon...

We have in our Italian house 100 amp service (at 234V) and it is damned near barely enough to get us by... Eventually I'll have to pony up some SERIOUS Euro to get real power into our property there, but I'm feeling the pinch of trying to get by on minimal service...

Go heavy, if you need to cut back then you can, but you then ALWAYS have the opportunity to "amp" back up. Doing an add-on later will be MUCh more 'spensive...

 

[86turbodsl]

Actually i asked him in #4 if he had done load calcs which is the correct way to figure out loads.

I stand corrected. My apologies.

 

[volleyball]

I read through afew of the arguments or post as we like to call them.
I cannot believe that a poco would not add meters. If it is a rental you need power for each unit as well as a meter for common areas. So a 2 family would get 3 meters.
All the OP needs to do is say that they will be rentals and problem solved for extra meters. It goes in his name until the tenant signs the lease which won't happen but it is 2 late then.
And many multiple units have 1 postal address. But it would not matter if the garage did get its own address. Maybe the apt. get occupied.

 

[alfredeneuman]

volleyball: I amended (corrected) it in Post #26 from 'meters' to 'services'

 

[Calum11]

It depends on how much stuff is used simultaneously rather than hoe much stuff you own. Anyway, I think 200 will be enough

 

[Strouty]

Shocking........... another charged discussion about who has more volts. Watt does it matter anyways?

 

[u3b3rg33k]

is it 220, 230 or 240?

 

[Lucid Moments]

So reading this and I get a lot lost. I am not an electrician and have never (and probably never will) read the NEC.

What is the downside to going with a higher amp service than is needed? In OP's situation (and mine) it is a new build so nothing will have to be taken out/redone.