How many 50A breakers can I put into a panel?

[remagenman]

Okay, been googling this but not coming up with a solid answer.

I want to add a 50 amp circuit breaker into my existing panel for a welder. I have the space for the breaker but already have 50a for the back-up generator(Costco Honeywell), a 50a for the range, 30a for dryer, 30a for heat pump plus all the other 20 and 15 amp breakers.

The closest I got to an answer was no more than 2x the panel amperage, so 2x200a=400 amps total combined?

If I count them all up now for whats currently in the panel they total 495 amps combined, so just a little confused.

Thanks.

ps, I have LED lights throughout the house.

 

[Elginz]

So the back-up generator runs off of your electric panel, I would think it would be the other way around.
Just saying I don't know either.

 

[mm08822]

It all depends upon the connected load (actual running load) and not the sum of the overcurrent protection breakers installed in the panel. This is what load calculations and diversity factors help rationalize.

"2x the panel amperage" is another urban myth.

 

[rockwithjason]

the load calculations for this are a little complex for a beginner. you have to determine which loads are continuous and which are non continuous and which if any are non co-insident. in practice you will not hurt anything by installing the 2p50. the panel is protected by the main breaker so you will not damage anything there. it doesn't sound like you are heavily loaded so i would guess that nuisance tripping probably won't be an issue. go for it.

 

[padroo]

I ever heard that rule of thumb, technically you could put 40, 20 amp breakers in a 200 amp main panel and that would total 800 amps. Just saying.

 

[wyliesdiesels]

codes from the urban myth code book die hard.

Another 50a breaker isnt gonna harm the panel.

 

[theoldwizard1]

codes from the urban myth code book die hard.

Another 50a breaker isnt gonna harm the panel.

Is there an "official" ratio of all breaker versus the main ?

 

[nh_yota]

You can put in as many as you can fit properly. You can fill a 42-space 200 amp panel with 42 20-amp breakers totaling 840 amps and it's legal as long as the load calculation is under 200 amps.

 

[sberry]

I have 600 or more in mine. As Wylie said, no rule.

 

[trashmanssd]

I was kinda wondering this also as I have 4 subpanels running off my main panel. Its 200 amp service and its a large complicated house with a lot breakers and a lot circuits but in reality we dont use all that much power. We have changed everything to LED or CFL for lighting and got a hybrid water heater and there is only my self and wife so we just dont use much off the house and we turn stuff off when not in use.

 

[mm08822]

Is there an "official" ratio of all breaker versus the main ?

No, just because a circuit is wired into a panel doesn't mean it has any load on it 99.9% of the time. Or it could be a 20a ckt with only a wall wort plugged in.
The breaker could be turned off or nothing connected to it.

You could put 10 welder recepts each on their own circuit in an outbuilding and only use your only 1 welder at any time - and how long do you run that?

A 40 space panel could be loaded with all 100a 2P cb's - no problem - its all about the actual load in use.
Continuous/simultaneous loads is where the main focus should placed - ac units, heat pumps, electric heaters, etc. You wouldn't run and electric furnace at the same time you are running ac.

 

[sberry]

At Self Help and More they really don't consider a common garage to be much additional load if there are not plans for ovens etc. About the only time I can recall a 200 overloaded was in a tavern, Friday night fish fry in hot summer weather and they had all electric fryers, 50A units, 5 of them, ac, hoods, coolers, refriges, 2 or 3 micros. Sun beat on a brown wall on the south side where the panel was mounted.
I changes it out to 325, added a 150 and moved the coolers, the AC and a couple micros off of it. They had a gob of stuff, I mean a gob, 2 or 3 times what you could possibly turn on in a house even with a hot tub or 2 and electric water heat. They did have gas for water and a gas grill.

 

[sberry]

I have 5 subs from my 200 shop at 60 and 5 more welders, one of the subs is for air comp. At the moment about an amp running besides the puter.

 

[86turbodsl]

The breaker is to protect the wire and any devices on that line. The panel main breaker is to protect the main line and breaker cabinet. Put as many as you want in there.

 

[Stuff]

I don't think that it is applicable here but there is a restriction with some panels which specifies the maximum amps per bus stab. Read the label as supposedly it can be as low as 110 amps. With the restriction you may not be able to put two 60amp breakers opposite each other. Or anything on the other side of a 100.

 

[remagenman]

Thanks, answers make sense. My generator is natural gas ran and only does a 5 minute self check on Tuesdays. So as long as I am not running everything in the house at the same time I should be good. Figured I'd ask people who have done this for a good answer.

Related question: when plugging in the new breaker do you turn off the whole main panel power switch (no power coming into breakers) or just make sure the 50a breaker is off when plugging in?

 

[checkthisout]

Yes turn off the main and understand that parts of the panel below the main are still hot.

Don't drop any screwdrivers or fasteners and wear face and body protection.

 

[sberry]

You certainly can, I don't but have done it hundreds of times.

 

[mm08822]

I don't think that it is applicable here but there is a restriction with some panels which specifies the maximum amps per bus stab. Read the label as supposedly it can be as low as 110 amps. With the restriction you may not be able to put two 60amp breakers opposite each other. Or anything on the other side of a 100.

What mfr has those restrictions and on which product series?

 

[wyliesdiesels]

Thanks, answers make sense. My generator is natural gas ran and only does a 5 minute self check on Tuesdays. So as long as I am not running everything in the house at the same time I should be good. Figured I'd ask people who have done this for a good answer.

Related question: when plugging in the new breaker do you turn off the whole main panel power switch (no power coming into breakers) or just make sure the 50a breaker is off when plugging in?

not necessary in regards to function or reliability.

If it makes u feel safer and more comfortable u can do so.

 

[remagenman]

not necessary in regards to function or reliability.

If it makes u feel safer and more comfortable u can do so.

Thanks. safer? We used to detonate IED's in Iraq by chucking hand grenades at them when we ran out of C4. I've had my share of unsafe practices at close range. Just didn't know if it mattered or not.

 

[terabitdan]

What mfr has those restrictions and on which product series?

My Siemens 200 amp is 115 amps per stab.


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[lakeroadster]

Related question: when plugging in the new breaker do you turn off the whole main panel power switch (no power coming into breakers) or just make sure the 50a breaker is off when plugging in?

I always kill the power to the panel whenever adding a breaker(s) and it's associated wiring. If you have that luxury it seems logical.

 

[sberry]

Not me, I have gobs of connected stuff and hate to interrupt the power if I can help it. But it isn't a hobby for me either.

 

[mm08822]

What mfr has those restrictions and on which product series?

My Siemens 200 amp is 115 amps per stab.


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I looked up a Siemens panel and there is an interesting new note on the panel label.

That was not always there. However it only references QT breakers and says nothing about QP's.
So I read this as: if I am not using QT's but only QP's there is no restriction. Otherwise it would say so???

QP 2 poles are available up to 125a while QT's are only available up to:
duplex - 30/30, triplex - 20/50-50/20, 30/30-30/30, quads - 50/50 - 30/30

 

[terabitdan]

That's the same load center I have, But I missed (ignored the importance of?) the QT qualifier. Mine was manufactured in 2001.


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[Radix2]

I have Siemens PL series panels and that note is not present. PL panels do not take the QT breakers, so it looks to be restricted to those alone.

 

[mm08822]

I have Siemens PL series panels and that note is not present. PL panels do not take the QT breakers, so it looks to be restricted to those alone.

I install Siemens copper buss PL panels typically, but my house has the plated buss version. I looked at my '95 Siemens vintage panel and it has no note. Next job I go back to or panel I buy, I will certainly be looking for those notes.

It doesn't make sense to me QT's restricted, QP's don't care. Same amount of current or more can flow out of a single buss stab using QP's. ???

 

[Radix2]

I install Siemens copper buss PL panels typically, but my house has the plated buss version. I looked at my '95 Siemens vintage panel and it has no note. Next job I go back to or panel I buy, I will certainly be looking for those notes.

It doesn't make sense to me QT's restricted, QP's don't care. Same amount of current or more can flow out of a single buss stab using QP's. ???

Looking at the pictures, do the stabs on the panels that take the QTs have notches so that they can't be installed on the PL panels without the notches?

Are there any other differences?...it doesn't look like the GE style panels that have the stab features/secondary stab to allow the narrow breakers.

I agree, it seems odd.

 

[mm08822]

Looking at the pictures, do the stabs on the panels that take the QTs have notches so that they can't be installed on the PL panels without the notches?

Are there any other differences?...it doesn't look like the GE style panels that have the stab features/secondary stab to allow the narrow breakers.

I agree, it seems odd.

So the note I found on QT breakers only appears in panels where # of circuits is greater than # of spaces. I have a 40/40 panel so that is why i didn't find the QT restriction. I Typically install 40/40's. A 30/40 or 42/60 panel has the restriction. And yes the qt breakers are keyed differently than the qp's.

So maybe the keying slot on the buss tab (less contact with breaker) is what drives the reduction.

 

[terabitdan]

This is the current label from Home Depot for the PL load centers. Made me wonder why, so I compared the contact area on QT and QP breakers, QP are bigger. These are a single 20 amp qp and double 20 qt.

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[mm08822]

It is not exclusive to PL series. It has to do with max # of circuits vs. max # of full size breakers.

You wont find that note on a 40/40 b/c it cant accept QT's.

 

[Radix2]

So it seems like the practical limitation is that they don't want QTs over 60a each facing each other on a stab.

For example, the 30-30 duplex should not have another directly across.

Yet you could put two 100 qps across from each other.

I think it has less to do with the buss itself and has to do with the short circuit rating of the panelboard - I notice that depending if a main breaker is used and type, that QTs are not allowed at all for some short circuit ratings. There is probably some quirk when QTs share a stab that their internals mess with the rating in the 20,000-100,00a mode. So probably nothing to do with overheating a stab at 110A on a buss rated for 200-225A.

My guess anyway

 

[kd3pc]

The breaker is to protect the wire and any devices on that line. The panel main breaker is to protect the main line and breaker cabinet. Put as many as you want in there.

the breaker is to protect the wiring. Does nothing to protect the devices on that wire.

Similarly the main breaker protects the wiring as well...does nothing to protect the downstream cabinet.

 

[sberry]

Sort of. It is to protect the buss from overload and against short circuit. A breaker may protect downstream equipment, not all stuff has added internal protection from short circuit. A buzzer welder is this way and so are most components in an electric range.
In both those items the breaker isn't for thermal for the wire, is simply an off on and short protection device. The calculated load is the protection for thermal.
Same for motor circuits. If it requires thermal its added.
Look at AC circuits, 40A breaker, 12 wire, same for buzzer welder, 50A, 12 wire.