Max breaker size for QO load center - Electrician Talk - Professional Electrical Contractors Forum
CLICK HERE AND JOIN OUR COMMUNITY TODAY, IT'S FREE!
Go Back   Electrician Talk - Professional Electrical Contractors Forum > Electrical Forum > General Electrical Discussion


Like Tree8Likes
  • 2 Post By CoolWill
  • 1 Post By joebanana
  • 1 Post By micromind
  • 1 Post By micromind
  • 2 Post By Forge Boyz
  • 1 Post By emtnut
Reply
 
Thread Tools Display Modes
Old 11-07-2019, 06:59 PM   #1
NDC
Senior Member
 
NDC's Avatar
 
Join Date: Jan 2016
Location: Ontario
Posts: 1,413
Rewards Points: 2,306
Default Max breaker size for QO load center

Does anyone know the max breaker size for a 200A QO push on panel?
I came across a 150A breaker that takes up 4 spaces but I've never used one. The panel doesnt list the max breaker size anywhere.
Its a QO-42m series T3B.
NDC is offline   Reply With Quote
Join Contractor Talk

Join the #1 Electrician Forum Today - It's Totally Free!

ElectricianTalk.com - Are you a Professional Electrical Contractor? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's the leading place for electricians to meet online. No homeowners asking DIY questions. Just fellow tradesmen who enjoy talking about their business, their trade, and anything else that comes up. No matter what your specialty is you'll find that ElectricianTalk.com is a great community to join. Best of all it's totally free!

Join ElectricianTalk.com - Click Here JOIN FOR FREE


Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ElectricianTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

Sponsored Links
Advertisement
 
Old 11-07-2019, 07:36 PM   #2
Senior Member
 
CoolWill's Avatar
 
Join Date: Jan 2019
Location: SC
Posts: 2,510
Rewards Points: 3,306
Default

I believe 125 is as large as they go before jumping 4 spaces.
micromind and MTW like this.
__________________
I'm With Her! Hillary 2016
CoolWill is offline   Reply With Quote
Old 11-07-2019, 08:45 PM   #3
Senior Member
 
Join Date: Dec 2010
Location: So.Cal.
Posts: 3,693
Rewards Points: 7,327
Default

Um.......I'll take 200 amps, for 200 Alex? What do I win?
JoeSparky likes this.
__________________
-------------------------------
~ She thinks I'm crazy, but I'm just growing old~
joebanana is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 11-07-2019, 10:21 PM   #4
NDC
Senior Member
 
NDC's Avatar
 
Join Date: Jan 2016
Location: Ontario
Posts: 1,413
Rewards Points: 2,306
Default

150amp breaker takes 4 slots but I thought some panels had maximums for branch circuit sizes. Is a 150 amp sub panel in a work shop fed from a 200amp main a bad idea? The home is has primarily gas appliances and the 150amp sub is for 2 car chargers at 48 amps each and they want room for expansion.
NDC is offline   Reply With Quote
Old 11-07-2019, 10:26 PM   #5
Bilge Rat
 
Join Date: Aug 2007
Location: Fernley, Nevada (near Reno)
Posts: 6,653
Rewards Points: 2,916
Default

As far as I know, if it's single phase, 125 is the max for 2 spaces and the adjacent spaces are limited to 40 amps.....I think........

They also make a 150 amp 2 pole that takes 4 spaces.

If it's 3Ø, the max for 3 spaces is 100 but they make a 110, 125 and 150 that takes 6 spaces. Same with the bolt on type.

A word of caution.......do not use a 2 pole 4 space breaker in a 3 Ø panel. If you do, when you turn it on, you'll have a bolted fault between A and C as well as A and B. If you put a 3 pole 6 space one in a single phase panel, it'll blow up too. These bolted faults will be at the line side, not the load side.
MTW likes this.
micromind is online now   Reply With Quote
Old 11-07-2019, 10:27 PM   #6
Bilge Rat
 
Join Date: Aug 2007
Location: Fernley, Nevada (near Reno)
Posts: 6,653
Rewards Points: 2,916
Default

Quote:
Originally Posted by NDC View Post
150amp breaker takes 4 slots but I thought some panels had maximums for branch circuit sizes. Is a 150 amp sub panel in a work shop fed from a 200amp main a bad idea? The home is has primarily gas appliances and the 150amp sub is for 2 car chargers at 48 amps each and they want room for expansion.
Nothing wrong with it.
MTW likes this.
micromind is online now   Reply With Quote
Old 11-07-2019, 10:58 PM   #7
Senior Member
 
Join Date: Nov 2014
Location: Pennsylvania
Posts: 695
Rewards Points: 52
Default

Or just get a lug kit and run a full 200A over to the shop.

Sent from my SM-G970U1 using Tapatalk
samgregger and MTW like this.
Forge Boyz is online now   Reply With Quote
Old 11-08-2019, 09:41 AM   #8
Band Member
 
emtnut's Avatar
 
Join Date: Mar 2015
Location: Eastern Ontario
Posts: 6,032
Rewards Points: 1,642
Default

Quote:
Originally Posted by NDC View Post
150amp breaker takes 4 slots but I thought some panels had maximums for branch circuit sizes. Is a 150 amp sub panel in a work shop fed from a 200amp main a bad idea? The home is has primarily gas appliances and the 150amp sub is for 2 car chargers at 48 amps each and they want room for expansion.
Personally I'd do a quick load calc.
Add the 2 chargers and whatever expansion they want, and see what you get.

Bet you a doughnut that the inspector will ask for it anyways.

I'm sure it will be OK, unless the 'expansion' they want is for a big hot tub or another car charger.
NDC likes this.
__________________
_____________________________________
Your Mother was a hamster, and your father smells of Elderberries. ... Now go away, or I shall taunt you a second time
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
emtnut is online now   Reply With Quote
Old 11-08-2019, 12:23 PM   #9
Senior Member
 
Join Date: Jan 2013
Location: Fleetside, RI
Posts: 649
Rewards Points: 1,263
Default

Could you just double lug the meter and forget the inside panel entirely?
samgregger is offline   Reply With Quote
Old 11-08-2019, 02:18 PM   #10
NDC
Senior Member
 
NDC's Avatar
 
Join Date: Jan 2016
Location: Ontario
Posts: 1,413
Rewards Points: 2,306
Default

Quote:
Originally Posted by emtnut View Post
Personally I'd do a quick load calc.
Add the 2 chargers and whatever expansion they want, and see what you get.

Bet you a doughnut that the inspector will ask for it anyways.

I'm sure it will be OK, unless the 'expansion' they want is for a big hot tub or another car charger.

Load calc comes in extremely low actually, under 68 amps.
NDC is offline   Reply With Quote
Old 11-08-2019, 02:20 PM   #11
NDC
Senior Member
 
NDC's Avatar
 
Join Date: Jan 2016
Location: Ontario
Posts: 1,413
Rewards Points: 2,306
Default

Do these larger breakers normally come with a neutral lug? Or which neutral lug should I buy for this panel for the large size conductor. I'll be installing 1/0 copper teck90 to the shed.
NDC is offline   Reply With Quote
Old 11-08-2019, 04:12 PM   #12
Senior Member
 
Service Call's Avatar
 
Join Date: Jul 2011
Location: Daytona Beach
Posts: 1,903
Rewards Points: 32
Default

The only other worry would be the buss stab rating. It is additive of all breakers on the stab not the load.
Service Call is online now   Reply With Quote
Old 11-08-2019, 10:02 PM   #13
Bilge Rat
 
Join Date: Aug 2007
Location: Fernley, Nevada (near Reno)
Posts: 6,653
Rewards Points: 2,916
Default

Quote:
Originally Posted by Service Call View Post
The only other worry would be the buss stab rating. It is additive of all breakers on the stab not the load.
This is why they limit the breakers on the opposite side to 40 amps......I think it's 40.......but it is limited.

Last edited by micromind; 11-08-2019 at 10:09 PM.
micromind is online now   Reply With Quote
Old 11-08-2019, 10:03 PM   #14
Work Speaks for Itself
 
phamousgrey's Avatar
 
Join Date: Mar 2018
Location: Ontario
Posts: 101
Rewards Points: 202
Default

that is the million dollar question actually. the breaker your putting in umm, doesnt typically have a name, but most ppl would assume thats a subpanel breaker your installing as i dont know of any load from a single phase panel that a residential home owner would need to supply a 150a load for . .lmfao.


but yeah, as far as the neutral is concerned...so long as the subpanel and loads on the subpanel DO NOT require a neutral [theyd have to be 240v loads] then your fine with supplying them with just 2 conductors and a bond wire. But if your subpanel needs 120v for anything regarding those loads, you need a neutral, and originally that subpanel shouldve been a disconnect/feeder feeding those 240v loads anyways without a neutral.


uh, short version;
240v loads - disconnects fed from a feeder aka 2wire w/bond
120/240v loads- distribution panel/subpanel with 3wire w/bond

Last edited by phamousgrey; 11-08-2019 at 10:10 PM.
phamousgrey is offline   Reply With Quote
Old 11-08-2019, 10:11 PM   #15
Bilge Rat
 
Join Date: Aug 2007
Location: Fernley, Nevada (near Reno)
Posts: 6,653
Rewards Points: 2,916
Default

Quote:
Originally Posted by NDC View Post
Do these larger breakers normally come with a neutral lug? Or which neutral lug should I buy for this panel for the large size conductor. I'll be installing 1/0 copper teck90 to the shed.
The ones I've installed didn't come with a neutral lug but I'm pretty sure you can buy a lug that takes up more than one space on the bar and will accomodate a larger wire.
micromind is online now   Reply With Quote
Old 11-08-2019, 10:25 PM   #16
Senior Member
 
Service Call's Avatar
 
Join Date: Jul 2011
Location: Daytona Beach
Posts: 1,903
Rewards Points: 32
Default Max breaker size for QO load center

Quote:
Originally Posted by micromind View Post
This is why they limit the breakers on the opposite side to 40 amps......I think it's 40.......but it is limited.


It’s limited to the max rating of the stub. For instance, ITE buss rating is 110 amps (I believe). Someone puts a 30/50 quad on both sides of the panel. That one stub now has the potential to carry 160 amps. 80 both sides because that one stub is sharing a 30/50 on both sides.

So if a stub is rated for 125 and you put a 125 on it. Technically you really can’t add any more breakers to that stub.

It’s rated on the total of the breakers, not the load.
Service Call is online now   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 12:14 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Our Pro Sites Network
ContractorTalk.com | DrywallTalk.com | HVACSite.com | PaintTalk.com | PlumbingZone.com | RoofingTalk.com