Panel capacity

[SiGmA_X]

GJ,

Can I please get a capacity check on this situation.

Panel is a Siemens G2030MB1150. It appears it has 20 spaces, 30 max circuits, and 10 max 2-poles.

"10 max 2-poles" = 5 240v circuits, right?

The existing circuits are 3 240v's and 13 120v's. I would like to add 4 more 240v's which would mean I need to tandem up a few breakers, but I think I'm limited to only add 2 more 240v breakers. Correct?

If I were to replace the main panel, would the whole house have to be brought up to code aka AFCI breakers? If I add a subpanel, can I skip bringing the main panel to code? Everything was permitted upon initial install and the later addition of whole-house AC, and this will be getting permitted as well.

Thanks!

 

[Cmreschke]

No. 10 max 2 poles is just that. 10 240 volt ckts

 

[SiGmA_X]

No. 10 max 2 poles is just that. 10 240 volt ckts

Oh man this is fantastic news. My first thought was 10 240's, but then I thought that would be too easy, so lets check with the good folks at GJ.

Thank you.

 

[Cmreschke]

I count 7 2 poles and 6 twins leaving you 1 ckt short. Now if you bought a twin 2 pole then it would fit. Might be better off adding a sub panel if you have the room.

 

[SiGmA_X]

I count 7 2 poles and 6 twins leaving you 1 ckt short. Now if you bought a twin 2 pole then it would fit. Might be better off adding a sub panel if you have the room.

Could you show me what you're counting? Can tandems only go on poles 11-20? So I could run the 5 240's on 1-9,11?

The whole-house AC is on poles 16/18 and was allowed by the inspector a decade ago. The other 240's are on 1/3 and 2/4.

I do have room to add a subpanel if I have to. Or upgrade the main panel if I don't have to upgrade to AFCI... I should probably mention I want to add 3 more 120v's also.

 

[Cmreschke]

You have 3? You want to add 4 more? That's 7 which takes up 14 spaces leaving you 6 twin able spaces which is 12 ckts. You have 13 though. So yeah if my math is right you need twins for some 2 poles also or add a sub panel. And now you want to add 3 more 120 you definitely in the sub panel range.

 

[SiGmA_X]

You have 3? You want to add 4 more? That's 7 which takes up 14 spaces leaving you 6 twin able spaces which is 12 ckts. You have 13 though. So yeah if my math is right you need twins for some 2 poles also or add a sub panel. And now you want to add 3 more 120 you definitely in the sub panel range.

Gotcha, of course. Makes sense.

If I am allowed to run 10 240v circuits and a total of 30 circuits, is there a problem with running a few twins for 2 poles? I would literally be maxing the panel out, but I don't have plans to add anything further.

 

[Cmreschke]

No problem with that just cost and finding them. Still limited by listing to 30 ckts.

 

[SiGmA_X]

No problem with that just cost and finding them. Still limited by listing to 30 ckts.

Gotcha. I didn't think prices were too bad when I was only considering a few.. Replacing all the breakers at $20ish a pop, yeah that adds up. Subpanel it is.

Is 100amp big enough for what I want? I suspect its vastly more than the max I will ever run at once. Welder, compressor, AC, lift, couple of outlets for small tools.

I'd want to run a 4 conductor branch circuit to the sub, remove the bonding jumper, and away I go? 4/4/4/6 copper feeder would be appropriate for the sub, right?

 

[Cmreschke]

Is 100amp big enough for what I want? I suspect its vastly more than the max I will ever run at once. Welder, compressor, AC, lift, couple of outlets for small tools.

It all really depends on if you do a load calc. Off top of my head, yeah, 100 amps is plenty.

Yes 4 wire feeder. Isolate the neutrals from geounds.

 

[Cmreschke]

#3 copper not 4

 

[wyliesdiesels]

Its a 20 space 30 max circuit. That means a max of 10 spaces can be tandems which equals 20 120v circuits + 10 single spaces equals 30 circuits.

u need 13 120v circuits/7 tandems= 7 spaces

U need 7 240v circuits= 14 spaces

U are short 1 space

Only option is a quad if u can get one for the panel.

 

[SiGmA_X]

Subpanel it is. I'm going to sketch up my desired circuit layout and make a list of what I want to do. 3 of the circuits go outside, so I'll need a metal box to attach EMT to a LB.

Thanks for your input.

 

[theoldwizard1]

Only option is a quad if u can get one for the panel.

a.k.a. Tandem 2 pole. Weird looking but some manufacturers DO make them.

 

[Norcal]

a.k.a. Tandem 2 pole. Weird looking but some manufacturers DO make them.

Technically a twin breaker is a 2 pole breaker but unless it's a GE, or obsolete Challenger, or a Crouse-Hinds, you cannot get 240V with them a quad is the only way.

 

[Cmreschke]

Technically a twin breaker is a 2 pole breaker.

Disagree, as it's only on 1 phase.

 

[Norcal]

Disagree, as it's only on 1 phase.

It is considered a 2 pole breaker in terms of the number of poles and the OP's panel is single phase so they are on the same leg . But other then GE the other two brands would fit and allow for 240V in a 1" space, just not proper.

 

[Cmreschke]

No its not. It's a single pole. A 2 pole switch is only 1 throw but operates from 2 phases of electricity. Because it has 2 breaker slots does not make it a 2 pole breaker. It operates from 1 pole (phase) of the panel.

 

[SiGmA_X]

What's the code on running NM-B in conduit? I have maybe 10ft of concrete wall that I am going to use EMT on, with a few boxes for bench power, but either end will terminate in a stud wall. I could transition to THHN if needed at both ends of the conduit. I'm seeing conflicting info online. Is there a change in fill spec?

What would the preferred studwall box to EMT transition be? Metal jbox on the surface of the wall?

How about through outside wall? Plan for outside wall is a 3-gang metal jbox in the studwall, with two liquidtight LB's on the outside. 1/2" for 10/3 for AC, 3/4" for 2 x 12/2, 1x8/2 for shed power.

Also, can I use 2 conductor 240 for an AC, lift, and compressor? 3 circuits. Compressor will be in the aforementioned shed and have a disconnect next to it. Lift won't (unless required) as it will be 4' from the panel.

I'm also right in understanding I can't have a switch for a circuit in the shed in the garage, right?

And do I need GFCI in a non commercial garage under NEC2014, and if so can I simply use a receptical or must I use a breaker?

 

[Norcal]

No its not. It's a single pole. A 2 pole switch is only 1 throw but operates from 2 phases of electricity. Because it has 2 breaker slots does not make it a 2 pole breaker. It operates from 1 pole (phase) of the panel.

Then please explain the limitation on the number of poles in a panel.

 

[wyliesdiesels]

NM-b is allowed to be ran in conduit INDOORS ONLY!

 

[Cmreschke]

Then please explain the limitation on the number of poles in a panel.

With this panel, I could put 10 twin breakers in the appropriate spots, that is fact. By your statements above that is putting 10 2 pole breakers in. Could I not put 4 more 2 pole breakers in the other remaining 10 slots giving me 14 2 pole breakers and 2 single pole slots left over say 1 and 2.

 

[Cmreschke]

Also, is a twin 2 pole 30 30 actually a 4 pole breaker then?

 

[SiGmA_X]

NM-b is allowed to be ran in conduit INDOORS ONLY!

The NM-B will strictly only be inside. In a wall or in EMT between two walls over a concrete stem wall. Can someone help me with conduit discount for EMT fed with NM-b? I can always go with THHN if that's easier.

What's the preferred method to get the EMT on the wall, too?

I want to run EMT down the wall from point to point in the below picture, with NM-b behind the sheetrock. Subpanel will be a few feet to the left of the frame, directly next to the main box.

 

[600SL]

Gotcha. I didn't think prices were too bad when I was only considering a few.. Replacing all the breakers at $20ish a pop, yeah that adds up. Subpanel it is.

Is 100amp big enough for what I want? I suspect its vastly more than the max I will ever run at once. Welder, compressor, AC, lift, couple of outlets for small tools.

I'd want to run a 4 conductor branch circuit to the sub, remove the bonding jumper, and away I go? 4/4/4/6 copper feeder would be appropriate for the sub, right?

100 Amp for Welder, Compressor, AC and lighting. All of those could very well be used at once. Unless they are all very small and you plan on never up sizing I would go with 200 Amps.

 

[SiGmA_X]

* AC is a little under 10amp (18k minisplit)
* Welder is a Millermatic 211, I doubt I'll get massively bigger one ever - at a max a Dynasty 280 which is 30amp.
* Compressor is a 5hp unit.

I don't think I'll have anything besides LED point of use lights on the subpanel. Overheads are on the house main panel already and any more I add will also be LED.

Seems to me that a 100a sub should be enough, if anything, I may have issues with the 150amp main panel. I could see getting close ish to capacity when running laundry, cooking, running the house AC, and doing work in the shop... But even then, it should be under the max. Would an inspector have any issue with it though?