adding hot tub circuit, no breaker slots left


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Old 05-02-10, 01:18 PM
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Question adding hot tub circuit, no breaker slots left

Hi,
I need to add a 220v circuit for a hot tub, but I have no slots left. My panel is a Square-D brand -- I assume that means I have to use all Square-D breakers? I cannot find any 1-inch wide double-pole breakers to replace some of the existing double-poles to create space for a 60A double. Am I forced to either install a sub-panel or replace the panel with a larger one? I can easily get to the wires where the A/C was installed and move the breaker over to the sub panel, and use that space for the sub-panel feed. But I would like to know if there is another option before I go to all that trouble.

Sub question... many of my existing general purpose 15 and 20 amp breakers are connected to each other with what seem like roller bars. So, for example, if the living room circuit trips to the mid-throw position, I have to shut it off AS WELL AS the circuit next to it, before turning them both back on. Why is that?

Thanks
 

Last edited by secretspy711; 05-02-10 at 01:19 PM. Reason: grammar
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Old 05-02-10, 01:25 PM
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Provide the model number and verify it is SquareD. With the model number one of the pros can tell you if it will take tandems or if you need to add a subpanel.
 
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Old 05-02-10, 02:56 PM
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Hot tubs can add a significant load to a service. You need to have a demand load calculation performed to see if your service will support a hot tub. You may need a larger service.
 
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Old 05-02-10, 04:27 PM
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Model number is RC2040M150CH, series M01. It is indeed Square D.

Currently it has:
1 30A 2-pole breaker
1 40A 2-pole breaker
1 50A 2-pole breaker
19 15A 1-pole breakers
9 20A 1-pole breakers

The main is 150A

Is a twin and a tandem the same thing? It may already have a bunch of those. There many 1-inch breakers with 2 switches on them.

Is there an online "calculator" that can help me do a load demand calc?

Here's a picture:

 

Last edited by secretspy711; 05-02-10 at 04:28 PM. Reason: added info
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Old 05-02-10, 04:48 PM
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The catalog number you have provided is for a All-In-One Ringless Horn OH/UG 150A piece of equipment which sounds as if the meter socket and panel are one unit. If this is the case, you would have to start with a load calculation and if the service will handle the additional load, install a subpanel. From appearances, I think it will handle the load, but you need to be sure.

http://www.schneider-electric.us/pro...r=RC2040M150CH
 
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Old 05-02-10, 04:58 PM
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I read it as having room or am I looking wrong?

http://www.squared.com/us/misc/faqIn...0,RC2040M150CH

The load center distribution section of this device is a 20 space/40 circuit design. It will accept up to 20 HOMT tandem or 10 HOMT quad branch breakers.
 
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Old 05-02-10, 06:15 PM
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I counted 36 circuits. The difference would be the full size two pole breakers.
 
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Old 05-02-10, 06:20 PM
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Yes, it has room, barely, but I detest tandems and quads and still recommend a subpanel. But, if the existing full sized 30A 2P and 40A 2P breakers were replaced with quads, it could open enough space for a 50A 2P for the hot tub. A HOMT1515230 will provide breaker space in two full sized spaces for 2-15A 1P circuits and 1-30A 2P circuit. A HOMT1515240 will provide breaker space in two full sized spaces for 2-15A 1P circuits and 1-40A 2P circuit. After moving four 15A circuits from adjacent spaces to the quads, there should be room for a HOM250, 50A 2P breaker, for the hot tub.

HomeLine® Circuit Breakers - Schneider Electric United States
 
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Old 05-02-10, 07:08 PM
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CasualJoe, THANK YOU for showing me those quads -- I had no idea there were breakers available in that type of configuration. I will heed your (and PCboss') advice, though, and do the load calc, and also look at what it would cost to add the sub-panel. However, I don't anticipate adding much in the future, so that's where part of my reservation about the sub-panel comes from.

Just curious, why do you detest quads and tandems?

What sub-panel would you recommend?

Can anyone answer one of my original questions: why are the handles on some of the 15A and 20A breakers ganged together in pairs?
 
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Old 05-02-10, 07:42 PM
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Those handle ties are used to ensure both legs of the circuit get turned off together.

I would stick with a Square D subpanel just for consistancy.
 
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Old 05-02-10, 08:14 PM
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ok, I'm using the load calculator here:

http://www.nojolt.com/load_calculations.shtml

BUT I am a little confused on what to enter for the number of "small appliance branch circuits". What counts as a small appliance branch circuit? Here is a better picture of how the panel is set up:



my house is 2600 sq. ft. water heater is gas, everything else is electric.

there is a circuit for an attic fan, but I don't have one.

Yes, there are 2 sumps.

I don't know what the 30A 2-pole is for.
 

Last edited by secretspy711; 05-02-10 at 09:25 PM.
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Old 05-03-10, 02:19 AM
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The small appliance circuits are for your kitchen and dining room receptacles. You should have two of them.
 
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Old 05-03-10, 05:49 AM
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the 2 pole 30 is probably the dryer.

I'd say go for a 200A service and 40 circuit panel.
 
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Old 05-03-10, 06:57 AM
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I think you need to invent a time machine so you can go back and slap the person that put a 20 slot panel in a 2600 sq ft house and pulled 31 circuits to it.

On a serious note, I'd recommend replacement of that panel with a full sized, 40 slot panel. You could go with your subpanel idea, but this one really needs to be bigger all by itself, IMHO.

It may be possible to upgrade to 200A without alteration to your service wiring, but given that the original contractor cheaped out on the panel I kind of worry that your current wiring shouldn't even be 150A, so probably not.

Increasing the service size would be wise in my opinion, but it comes with a significant cost so definitely weigh that in. Given your panel usage, 150A with a new 60A hot tub might be pushing things a bit, particularly on a hot day with the A/C running and someone baking cookies and doing laundry at the same time.
 
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Old 05-03-10, 08:11 AM
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ok, so I looked at my panel and meter, and they both say 200 amps max., even though the main breaker is 150A. What would be involved in a service upgrade to 200A? I know it is expensive, (I've seen numbers anywhere from $1000 to $9000 on the net). Strike this question: Since panel and meter can handle 200, is it as simple as getting a 200A main breaker installed? Is it possible that I already have 200A service, and there was a sale on 150A breakers when my house was built 9 years ago? :-P

So, just curious... what happens if, on a hot day with the A/C running, someone is baking cookies and doing laundry at the same time, and the hot tub is running? If it overloads, will the main breaker simply trip? Or is it more serious than that? I'm wondering if I can install the hot tub with service as-is, and if I have problems with breakers tripping, THEN upgrade to 200?
 

Last edited by secretspy711; 05-03-10 at 09:02 AM.
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Old 05-03-10, 08:16 AM
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Normally the wires feeding the panel are no larger than they need to be, ie you would not install 200 amp conductors to feed a 150 amp panel. Can you tell us the wire or cable size currently feeding the panel?

Using the example you might use too much electricity and the main breaker would trip.
 
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Old 05-03-10, 08:40 AM
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I just called the electric company. The woman in the engineering department I spoke to was unable to tell me the number of amps that my electrical service is rated for. She said I would have to call an electrician to hook up an ammeter to find out how many amps I'm pulling. I told her that I wasnt asking how many amps I am pulling, but how many amps my "service" is. She gave me the same answer. Shouldn't they be able to answer this question? ugh.

Ok, so I've educated myself a little since I wrote that, so I grayed it out. "Service" takes many factors into account -- it's not quite the same analogy as, for example, upgrading the speed of cable internet service.

So, if I open up the panel, and find out that the cables and conduit can handle 200A, then all I'd have to do is replace the main 150A breaker with a 200A breaker, right? (because the panel and meter can already handle 200). If the cables and conduit CANNOT handle 200, then it gets much more expensive from there...because I would need replacement of underground wires, right?

I could tell you what AWG the cables are, but I'm away from my panel right now. I'll pull the cover off when I get a chance (after shutting off the main of course, and being careful not to touch the main feeds!) and report back.

I'm not trying to cheap out, just want to find out as much as possible first.
 

Last edited by secretspy711; 05-03-10 at 09:16 AM.
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Old 05-03-10, 09:19 AM
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Originally Posted by secretspy711 View Post
I just called the electric company. The woman in the engineering department I spoke to was unable to tell me the number of amps that my electrical service is rated for. She said I would have to call an electrician to hook up an ammeter to find out how many amps I'm pulling. I told her that I wasnt asking how many amps I am pulling, but how many amps my "service" is. She gave me the same answer. Shouldn't they be able to answer this question? ugh.

Ok, so I've educated myself a little since I wrote that, so I grayed it out. "Service" takes many factors into account -- it's not quite the same analogy as, for example, upgrading the speed of cable internet service.

So, if I open up the panel, and find out that the cables and conduit can handle 200A, then all I'd have to do is replace the main 150A breaker with a 200A breaker, right? (because the panel and meter can already handle 200). If the cables and conduit CANNOT handle 200, then it gets much more expensive from there...because I would need replacement of underground wires, right?

I could tell you what AWG the cables are, but I'm away from my panel right now. I'll pull the cover off when I get a chance (after shutting off the main of course!) and report back.

I'm not trying to cheap out, just want to find out as much as possible first.
Not only do the wires in your panel have to be of sufficient size, but if you have an overhead service drop, the wires from the utility to your weatherhead have to be of sufficient size.

I don't think your power utility rep had any idea what they were talking about. They may need an electrician to go out and confirm what size service your home is rated for, but for pete's sake it should be in their documentation somewhere. What she was talking about is having a utility electrician do a load check of your home, which isn't what you were requesting. It may be helpful to have it done, however, to see if there really is any need for an upsize of your service. Given your circuits, I doubt you have enough room for a 60A circuit, but who knows, right?

Please be careful when you pull that panel cover off. Those wires are still electrified. The only way to turn them off is to remove your meter from it's socket, and the utility must do that. You can take the cover off, but just be careful.

If, after you take the cover off, you have the correct size wire for a 200 amp service you can contact the power company and confirm that their transformer and wires are capable of handling that load. Then, if they agree, you can install the 200 amp breaker and you're done. If the wires are too small, you'll need to coordinate with them and an electrician to have the service upgraded. I do not recommend upgrading your service as a do-it-yourself project.
 
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Old 05-03-10, 05:04 PM
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I took the cover off but I still can't get to the incoming cables to see what size they are. To do that, I'd have to cut this little lock thingamajig to open the cover on the meter itself. I assume if I do that I will get fined...

On the electric company FAQ site, one of the questions says,

Q. Can I cut the seal on my meter?
A. No. Please contact Engineering Services for more information.

So I guess I will have to call the company again or an electrician. Hopefully I will get someone a little more competent this time.

The conduit is at least 2 inches, though... which means the cables may be large enough for 200A service. But it's not the complete story.
 
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Old 05-03-10, 07:10 PM
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You could try to see a size on the wires inside your panel. The lugs where the large wires terminate are hot all the time. Do not touch them.

The 2" conduit may not be a clue. Power companies sometimes have a minimum size.
 
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Old 05-03-10, 07:37 PM
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You could by a foot of 0/2, 0/3, and 0/4 strip some of the insulation and try visually comparing the size.
 
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Old 05-03-10, 09:04 PM
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Just curious, why do you detest quads and tandems?
Your situation is a perect example of why I don't like quads and tandems. The manufacturer uses a typical 20 circuit box and squeezes 40 circuits into it. The end result is a cramped interior with wires being squeezed into the space of half as many circuits in a typical panel. No matter how hard you try, it will never be as neat and orderly as a 40 circuit panel.

QUESTION: You never said what kind of heat you have, but I saw what I thought was a single pole 15 amp breaker that was marked furnace so I am assuming it is gas. Is that correct?

As far as upgrading to 200 amps. I believe you have a OH/UG combination meter/panel rated to handle up to 200 amps, but with a 150 amp main breaker. Do you have an overhead or underground service? Your panel/meter combo is rated for either.

If you upgrade to 200 amps, I wouldn't bother with the load calculation, you'll be fine.

So, if I open up the panel, and find out that the cables and conduit can handle 200A, then all I'd have to do is replace the main 150A breaker with a 200A breaker, right? (because the panel and meter can already handle 200). If the cables and conduit CANNOT handle 200, then it gets much more expensive from there...because I would need replacement of underground wires, right?
This statement leads me to believe it's an underground service.

If you want to upgrade to 200 amps, the service entrance wiring must be upgraded to either 2/0 copper or 4/0 aluminum. In your case, this probably only means between the meter and main breaker. Then, change the main breaker to 200 amps. You'll have to inform the power company of any increase in load, that is what they typically size their feeder to, not your service size. If the underground feeder to your home belongs to power company, they may charge you for any upgrade on their part, no two power companies are the same. If you own the feeder, you'll probably have to bring it up to a 200 amp rated feeder.

What sub-panel would you recommend?
I normally never recommend the Square D Homeline because it has aluminum bus, but in your case, I would recommend it for consistency with the main panel.
 
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Old 05-04-10, 08:03 AM
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CasualJoe,
Yes, furnace is gas.
Service is underground.

My power company is responsible for service up to the meter. (I guess that includes the meter itself because of the seal on it.)

Ray and PCBoss,
The only wires I can see inside the panel are those from the main breaker to all the other breakers. I cannot see the feeder wires to the meter, or the wires from the meter to the main, without cutting the seal on the meter, which, according to the company's website, I can't do. But I'm tempted to do it anyway since they couldn't provide me with the correct information over the phone.

I guess I'll have to call again and hope for someone more informed.
 
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Old 05-04-10, 07:16 PM
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My power company is responsible for service up to the meter. (I guess that includes the meter itself because of the seal on it.)
Typically, the power company would be responsible for the underground feeder up into the meter socket to the line side lugs. They also own and are responsible for the meter. The customer owns and is responsible for maintaining the meter socket. In my area, it's not unusual for an electrician on a service call to cut the seal to access the inside of the socket for inspection/maintenance and then call the power company to have the meter resealed, but this can vary by area and power company. If you get the opportunity to peek inside the socket, don't be too surprised if the power companies underground feeder is smaller than your service entrance wiring. They size feeders and transformers to connected load and not the size of your main breaker. That is why it is important to notify the power company if you plan on adding a significant load.
 
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Old 05-05-10, 08:53 PM
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Cool calculating amperage

Ok, some of you sparkies can check me on this...

Using the meter at the breaker box, I ran a little test. It goes something like this:

1.) I turned on some lights, the oven, the dryer, and the A/C. I suppose I could have turned on the washer too, but I don't know at what point it heats the water.

2.) The meter is digital, so I counted the number of times the little blocks in the corner changed. I counted 50 changes in 23 seconds. Each change is one watt-hour, right? The Kh factor is 1.0.

3.) Watts = 3600 * (number of changes) / seconds
=3600 * 50 / 23 = 7,826 watts.

4.) Amps = watts/volts = 7,826/240 = 32.6 amps.

So that's 32.6 amps of electricity flowing through the meter. Is that right? That seems a little low for 3 big appliances running at the same time, doesn't it? I was figuring it would be a lot closer to 100. Am I doing it right?
 
 

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