# # of breakers in a Siemens G1836ML13150CU?



## acro (May 3, 2011)

*# of circuits in a Siemens G1836ML13150CU?*

I am installing this 3 phase panel, which is an 18 space panel and I will be using a 3 pole main breaker, but will be using it for single/double pole loads. My plans will only leave one or two spaces free initially. Ideally, I would install a larger panel, but I have this one on hand already.


My question is... When can, and how many double breakers be used for single phase circuits with this panel?

I do not see the # of circuits listed on the label. I assume this panel may not be listed for the double breakers, but would like to know if that is correct.

If it is an 18 circuit maximum, do the 3 circuits used by the main breaker count towards that number? If not, could I use up to 3 double breakers if needed?













Thanks


----------



## sbrn33 (Mar 15, 2007)

The pic is messed up (tinypic.com) but that panel is rated for single pole tandems. So theoretically you could get 30 single poles out of it.

Do they make a hold down kit for a 3 pole breaker??


----------



## B4T (Feb 10, 2009)

I see it as max of (18) single pole breakers.. (6) 3-pole breakers.... (9) 2-pole breakers...


----------



## B4T (Feb 10, 2009)

What size main breaker are you using??


----------



## acro (May 3, 2011)

How do you come up with 30?

Yes, there is a hold down retainer available. Says so on the label - MBR-1.

However, when I priced the breaker and asked my supply house about a hold down yesterday, they said they have never sold one and did not know what I was asking for. Hopefully they can order it now that I have a part# for them.


----------



## B4T (Feb 10, 2009)

Dam... I didn't see the A & B... that means twins can be used at any finger so max of circuits would be (36)...

Then you need to take (6) away for main...


----------



## acro (May 3, 2011)

B4T said:


> What size main breaker are you using??



I was planning on a 125, as that is what the panel is rated for.

I am sizing my primary and secondary conductors for a 50kva transformer, should we decide to purchase one in the future.


However, my current transformer is only a 30kva. Am I correct in thinking if I protect the primary at 125% of this(45amps), I just need to protect the conductors on the secondary?

Therefore the use of a larger breaker(125a) than would normal for 125% of the 30kva secondary.


----------



## acro (May 3, 2011)

B4T said:


> Dam... I didn't see the A & B... that means twins can be used at any finger so max of circuits would be (36)...
> 
> Then you need to take (6) away for main...



The A&B thing for the labels had me wondering too - just forgot to mention it in my original post.

So.. that is how sbrn came up with 30?


----------



## B4T (Feb 10, 2009)

acro said:


> I was planning on a 125, as that is what the panel is rated for.
> 
> I am sizing my primary and secondary conductors for a 50kva transformer, should we decide to purchase one in the future.
> 
> ...


Don't think that will work.. I can't read the specs on the left side of sticker.. but there there is a (110) amp. limit per stab on Murray panels.. only the lugs you are using are rated at 125A....


----------



## B4T (Feb 10, 2009)

acro said:


> The A&B thing for the labels had me wondering too - just forgot to mention it in my original post.
> 
> So.. that is how sbrn came up with 30?


Yes... sometimes you will see a panel that will only take twins in certain spots on the bus...

Also the first (2) numbers on panel number will give you the max. of circuits using full size breakers and the maximum number of circuits using twins.. *1836*


----------



## acro (May 3, 2011)

B4T said:


> Don't think that will work.. I can't read the specs on the left side of sticker.. but there there is a (110) amp. limit per stab on Murray panels.. only the lugs you are using are rated at 125A....



Hard to tell from that photo I found online, but my panel is rated for 125a main breaker, and each stab is rated for 110a like the Murray.

Now that you mention the part#...36. It does seem to indicate that they can be doubled up.


----------



## acro (May 3, 2011)

Strange, I checked two supply houses and 100amp is the largest 3 pole breaker I can get.

Does that seem right?

Did they discontinue the 125?


----------



## acro (May 3, 2011)

For what it's worth, I found this.
http://www.frostelectric.com/pdf/Catalog/Panels%20Breakers%20and%20Meters.pdf

It actually says the panel is rated for 150amps - not sure how they get that.

And they do show a 125a breaker, but it is a two pole. Q2125
Biggest 3 pole is in fact a 100 amp - Q3100

The only way I can see properly using the 125a DP in this panel would involve some other form of protection larger than a main breaker in this panel.


Since I am pretty sure I need some protection in the circuit feeding this and don't want to install another box, looks like 100a is my best bet.




For conversation sake, with the primary of the transformer protected at 125%, could I skip the protection on the secondary side in any circumstance?


----------



## McClary’s Electrical (Feb 21, 2009)

Is this a service?


----------



## McClary’s Electrical (Feb 21, 2009)

By the way, that is an 18/36


----------



## B4T (Feb 10, 2009)

I found one.. http://www.amazon.com/dp/B0052MCUAY/?tag=tvtest2-20


----------



## McClary’s Electrical (Feb 21, 2009)

Unless this is a service, he doesn't need it.


----------



## acro (May 3, 2011)

mcclary's electrical said:


> Is this a service?



I don't think so, but honestly, I never considered that it could be.


Service from the POCO is 480 3 phase. I am installing this panel and transformer for the 240/120. Side benefit is the 3 phase 240.

I don't really need the 3 phase 240, but this 3 phase panel will definitely let me balance my load on the transformer. And possibly add a 3 phase device if I can't run it from the 480. My only other option was to let the 3rd phase secondary float.


A little off topic, but I do have a 208 3 phase heater I am going to modify and use. But I think I am just going to use single phase, as the full output is more than I need for the size of my room.

Now, I'm rambling...


Other than my control transformers, this is the only source of 240/120 at this location. This panel is in the same room as the main disconnect for the 480.

So, is it a service?


----------



## acro (May 3, 2011)

B4T said:


> I found one.. http://www.amazon.com/dp/B0052MCUAY/?tag=tvtest2-20


No pictures, so I don't know for sure, but it does not look right.



> Siemens QPJ breakers are intended for use only in Siemens EQIII three-phase load centers from 125-400 Amps. The breaker takes up six 1-Inch breaker positions, three on each side of the panel.


----------



## mbednarik (Oct 10, 2011)

mcclary's electrical said:


> Unless this is a service, he doesn't need it.


Only if he installs a OCPD between the trans and the panel. This is other than a single phase (2 wire) or a delta 3-wire installation so a secondary OCPD is required per 240.4 F. The panel also required some sort of OCPD somewhere, not necessarily a main breaker, per 408.36.


----------



## Norcal (Mar 22, 2007)

If your X-former secondary is 120/240V 3Ø, you will not be able to use twin breakers on the high leg, & if trying to save space why not use a fused safety switch or a enclosed circuit breaker to protect the X-former secondary?


----------



## acro (May 3, 2011)

Good points


----------



## Elephante (Nov 16, 2011)

If B is your high leg use C and A and put a sub panel.Don't know if that's code or not. I think that would work.


----------



## Jlarson (Jun 28, 2009)

Elephante said:


> If B is your high leg use C and A and put a sub panel.Don't know if that's code or not. I think that would work.


Nothing requires it but it's often a good way to roll. A 3 phase panel for obviously your 3 phase loads and any single phase 2 wire 240 stuff, and a single phase panel for 120 and 3 wire 240 loads.


----------



## acro (May 3, 2011)

I know that two separate panels would present clear separation of the loads, but it definitely makes the install more complex and expensive. Something I need to avoid with this one. 


If I where to instal separate panels, one of the things that I mentioned before - load balancing - would not be as easy. In this instal, 90%+ are single phase loads. So the 3 phase transformer would be very unbalanced.

I don't do many of these installs, but would think that would be a concern. Is it not?



I definitely will be mindful of the high leg buss with single phase breakers. And will label the slots accordingly.


----------



## acro (May 3, 2011)

Norcal said:


> If your X-former secondary is 120/240V 3Ø, you will not be able to use twin breakers on the high leg, & if trying to save space why not use a fused safety switch or a enclosed circuit breaker to protect the X-former secondary?


You're talking about secondary loads, right?


Why do you say that? All of the phase-phase readings will be 240v. The high leg is only "high" when referenced to the neutral. Something that is not a factor with twin breakers by themselves. Now, if the load also requires a neutral, then I need to be concerned, but not always.


----------



## Elephante (Nov 16, 2011)

acro said:


> I know that two separate panels would present clear separation of the loads, but it definitely makes the install more complex and expensive. Something I need to avoid with this one.
> 
> 
> If I where to instal separate panels, one of the things that I mentioned before - load balancing - would not be as easy. In this instal, 90%+ are single phase loads. So the 3 phase transformer would be very unbalanced.
> ...


How would you balance the high leg anyway? All the sp and dp are going to be on A and C leg no matter what, In that panel or the a new sub.


----------



## acro (May 3, 2011)

Elephante said:


> How would you balance the high leg anyway? All the sp and dp are going to be on A and C leg no matter what, In that panel or the a new sub.



That may be right for most installations. I don't know all of the 2 pole loads I will have, but if they don't require a neutral I can put them on B. And therefore attempt to balance the load.

I am specifically planning on some resistance heaters - so no neutral needed for them. Unless someone can prove to me otherwise. I am only going to use two or 3 phases and a ground. The reason I say that is that they are 3 phase heaters, but I don't think I will need their full output.


Hell, right now, it's all in my head. I may change my mind when I start hooking things up, but that's how I think it will be.


----------



## Dennis Alwon (May 9, 2009)

I have never seen a 3 phase panel that would accept twins but this one seems to. What you have here is an 18 circuit for any combo of full size sp breakers or 36 cir for twin breakers.

Each side of the buss has 9 stabs that will take sp or twins. So you can put 8 dp on each side and 2 sp circuits left over or you can also use dp twins...


----------



## acro (May 3, 2011)

Yep.


----------



## Elephante (Nov 16, 2011)

acro said:


> You're talking about secondary loads, right?
> 
> Why do you say that? All of the phase-phase readings will be 240v. The high leg is only "high" when referenced to the neutral. Something that is not a factor with twin breakers by themselves. Now, if the load also requires a neutral, then I need to be concerned, but not always.


You can't twin the high leg but you can dp that leg ex. AB. It seems like it would work without adding a sub.How many branch circuits do you have? And are some of your lights 240 dp you said?


----------



## Norcal (Mar 22, 2007)

Any breaker that is installed on the high leg buss stab must be rated 240V, standard breakers are rated 120/240V so they cannot be used, be prepared for sticker shock though, have heard a 2 pole 240V rated breaker is around $90, but YMMV....


----------



## acro (May 3, 2011)

I will have around 16 circuits circuits initially. Only one 240v circuit with neutral-other 240's is the previously mentioned heater. Maybe a 240v lighting circuit in the future. The rest are 120v.

Thanks for the heads up on the breaker rating. I might not have caught that. I haven't checked on a DP 240 yet, but my cost for the 3p 100a main is $92 - so same ballpark.


----------



## Elephante (Nov 16, 2011)

Yea i think that will work fine. just needs to be balanced for your transformer.


----------



## Greg (Aug 1, 2007)

I'm surprised you guys missed the fact that this is an 18/36 panel rated for 3 phase 150A at 240v with copper buss, main lug. The model number tells you everything you need to know.

Edit: Guess I should've read all the posts. The specs of the panel were noticed.


----------

