Add 50 amp breaker to home panel?

Reply

  #1  
Old 07-21-14, 08:39 AM
Member
Thread Starter
Join Date: Jul 2014
Location: United States
Posts: 6
Add 50 amp breaker to home panel?

Good morning,

My parents want to add a 50 amp breaker to my existing home electrical panel to plug in their RV when they come to visit me. My Dad is very handy and has some experience with electrical wiring. He thinks he can simply add the 50 amp breaker to the box (there is room from what I can tell) and then add an outlet near our well where there is another electrical box. The main panel is 200 amps but the Sub-panel (I think that's what it is called) is apparently connected to it from the labels I see written. He would be adding to the main 200 amp panel.

I have attached a couple of pics of the panel for review. If this is really this easy I have no problem with him doing it, however if it is much more complicated I would want to hire an electrician for safety of all involved. Any tips or advice is greatly appreciated. Thanks!

Alisha
 
Attached Images   
Sponsored Links
  #2  
Old 07-21-14, 09:23 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,213
It looks like there may be room for an additional 2 pole breaker at the top of the existing panel. How many amps is the subpanel fed with? Would it make more sense to feed the new circuit from the subpanel?
 
  #3  
Old 07-21-14, 09:32 AM
Member
Thread Starter
Join Date: Jul 2014
Location: United States
Posts: 6
I'm a total novice here but from what I can see, the top 2 say 40 on them (and are unlabeled for what they go to), then the next 2 (which are labeled Subpanel) say 100 on each of them. The inside panel has many 15 ones in it and the panel says it is rated 100amps. The one I am showing is the one on the outside of the home, nearest to where they would park the RV so I think that is why he wants to do it in the outside one. Does that help?
 
  #4  
Old 07-21-14, 01:43 PM
bigboypete's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2013
Posts: 218
It looks like there may be room for an additional 2 pole breaker at the top of the existing panel. How many amps is the subpanel fed with? Would it make more sense to feed the new circuit from the subpanel?

An appropriate load calculation must be done before adding such a significant load to the service.
 
  #5  
Old 07-21-14, 01:59 PM
Member
Thread Starter
Join Date: Jul 2014
Location: United States
Posts: 6
An appropriate load calculation must be done before adding such a significant load to the service.
Ok, I'd be happy to do that if I knew how. I found the link to http://www.doityourself.com/stry/cal...breaker-load#b but to me (and granted I have no idea what I am doing), it appears that this is calculating the load to the specific breaker, what I need to know is if the panel itself can handle this additional 50 amp breaker that would be completely dedicated to the RV with nothing else on it.

Sorry if I am misunderstanding. My Dad seems to think it's no big deal and I just want to run it by others before I let him do it.
 
  #6  
Old 07-21-14, 03:05 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,659
  #7  
Old 07-21-14, 03:22 PM
Member
Thread Starter
Join Date: Jul 2014
Location: United States
Posts: 6
These calculators are a bit too complicated (and time consuming for me to go around and look at all my electrical items) for me. I think I'm just going to ask them to either use an adapter to convert down to 20 amps or have them hire an electrician. Thanks for all of your help, it's just more than I can do with 3 little kids running after me, LOL!
 
  #8  
Old 07-21-14, 04:09 PM
Member
Join Date: Jul 2014
Posts: 7
The amount of amp load on the panel has nothing to do with the amount of breakers or what they are labeled. There are two ways to find out how many more amps the panel can carry. 1)(the right way) see if your father has an electrical meter that has an ammeter(a clamp that goes around wire and measures the amount of amps based on their magnetic field) or buy one(75$ for a decent one) after you have a meter turn on everything the panel feeds like the dishwasher, water pump for sprinklers, outdoor lights etc and put the ammeter clamp around the feeding wire(the one connected to the 100 amp breaker) and read the amps being used or 2)(the wrong way) let your dad hook up the 50 amp breaker and plug his rv; if the subpanel cannot handle the load the 100 amp main breaker for the outside subpanel will trip, if not the panel can handle it.
 
  #9  
Old 07-21-14, 04:24 PM
Member
Thread Starter
Join Date: Jul 2014
Location: United States
Posts: 6
Thanks! He does have an ammeter (not sure if it has a clamp but I know he's used it before with the little metal prong that goes into an outlet to take a measurement).

Quick question though:
if the subpanel cannot handle the load the 100 amp main breaker for the outside subpanel will trip, if not the panel can handle it.
In my head, the panel in question where he would want to add the breaker is the main panel (outside, as pictured) and inside it it shows there are 2 100 amp breakers going to the panel inside the garage (I believe that is right as they are labeled sub-panel and the inside panel states it is 100 amp capacity). My question is this: if he puts the 50 amp breaker either in the slots currently labeled 40 that appear to be unused or in the free slots will it trip just the same if it cannot handle the load? I just want to make sure I understand right if his ammeter doesn't have a clamp.

Thanks again!
 
  #10  
Old 07-21-14, 04:36 PM
Member
Join Date: Jul 2014
Posts: 7
Correction* you would want to measure the amps on the feeder wire(typically the thickest wire that is hooked to the breaker with the highest amps which is considered your main breaker) of whatever panel you will be putting the 50 amp breaker in. (I think I misread which panel you were going to be using earlier) or just do option #2 which if the panel you will be adding to is the 200 amp panel it will most likely not overload the panel since most households don't use close to 200 amps but again if it does overload the panel as long as your main panel has a main breaker that the feeder wires land on it will simply trip the main breaker and your dad will be out of luck
 
  #11  
Old 07-21-14, 04:40 PM
Member
Join Date: Jul 2014
Posts: 7
Yes no matter where you put the breaker it connects into the bus bar that feeds your panel. Unless he is looking to use a 240 volt outlet, he will be using a single pole breaker and that should fit in any slot.
 
  #12  
Old 07-21-14, 04:42 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,659
he's used it before with the little metal prong that goes into an outlet to take a measurement).
That's a multimeter not a clamp on amp meter.
 
  #13  
Old 07-21-14, 04:43 PM
Member
Join Date: Jul 2014
Posts: 7
Does the main 200 amp panel have a breaker labeled 200 amps?
 
  #14  
Old 07-21-14, 05:10 PM
bigboypete's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2013
Posts: 218
MAYTUMS88 WROTE
if the panel you will be adding to is the 200 amp panel it will most likely not overload the panel since most households don't use close to 200 amps but again if it does overload the panel as long as your main panel has a main breaker that the feeder wires land on it will simply trip the main breaker and your dad will be out of luck
Sorry, your methodology is wrong. Waiting for a main breaker to trip out is not how to calculate additional demand on a service. Also suggesting that someone with no electrical ability stick testing devices around energized feeder wires is also irresponsible and dangerous.
 
  #15  
Old 07-21-14, 05:30 PM
Member
Join Date: Jul 2014
Posts: 7
If her father has dealt with electrical in the past I do not see the harm of him doing basic troubleshooting with a meter(if not you would need an electrical license to purchase one). Purposely tripping a main breaker is not the correct way of calculating demand, though is effective, cheap and safe because the breaker is manufactured to trip due to overload many times before damaged.
 
  #16  
Old 07-21-14, 06:08 PM
Member
Thread Starter
Join Date: Jul 2014
Location: United States
Posts: 6
Does the main 200 amp panel have a breaker labeled 200 amps?
Yes, there are 2 (connected to each other, there's actually 4 "slots" taken by this but each of the 2 are connected to something that says 200 and then those 2 "200" Labels are connected to each other) that say 200 on them but next to them they are labeled "Service Disconnect".

I'm assuming this would not be dangerous, or likely to catch my home on fire. From what I understand, it would simply tell me if the panel could handle the load when they come.
 
  #17  
Old 07-21-14, 06:34 PM
Member
Join Date: Jul 2014
Posts: 7
Yes if the main breaker wasn't capable of interrupting an overload, introduced by you or otherwise then you would be living at risk. Although it's not ideal practice, every Electrician I have ever met who trips a breaker but knows the cause of the trip will fix whatever caused the overcurrent and re-energize the breaker.
 
  #18  
Old 07-21-14, 06:45 PM
Member
Join Date: Jul 2014
Posts: 7
I better clarify that before people start getting angry. Every electrician I know will reset the breaker if they know it has been overloaded. If the cause is a short-circuit(touching two phase or hot wires together) or a ground fault(touching a phase or hot wire to ground) then the breaker could be damaged internally due to high currents(thousands of amps over a split second), heat caused by the current, and the magnetic field caused by the current. In those cases the breaker needs to be inspected for internal damage before re-energized.
 
  #19  
Old 07-21-14, 07:15 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,213
I'm a total novice here but from what I can see, the top 2 say 40 on them
I was looking at the two twistouts at the top, it looks like the panel will accept one more 2 pole breaker there. You have 200 amps. Unless you have a large all electric home there is no problem adding an RV outlet to your 200 amp service. From looking at your panel I can see you do not have that kind of load.
 
  #20  
Old 07-22-14, 03:58 AM
bigboypete's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2013
Posts: 218
CASUAL JOE WROTE- I was looking at the two twistouts at the top, it looks like the panel will accept one more 2 pole breaker there. You have 200 amps. Unless you have a large all electric home there is no problem adding an RV outlet to your 200 amp service. From looking at your panel I can see you do not have that kind of load.

Sorry Joe, but that is an assumption. You can not safely say by looking at a grainy photo of the circuit directory that its appropriate to add a 50A load to this service.
 
  #21  
Old 07-22-14, 05:45 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,360
You don't need to run around the house to get the information for all your appliances. The spreadsheet will have default values. At most you would need HVAC values.
 
  #22  
Old 07-22-14, 07:03 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,213
Sorry Joe, but that is an assumption. You can not safely say by looking at a grainy photo of the circuit directory that its appropriate to add a 50A load to this service.
Technically you are correct, but in reality no one will do a load calculatoion on this service. Without relying just a little on the panel schedule someone would have to trace and verify each circuit and the reality is that will not happen. We aren't talking about adding a 50 amp load, just a 50 amp circuit.
 
  #23  
Old 07-22-14, 08:41 AM
bigboypete's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2013
Posts: 218
Technically you are correct, but in reality no one will do a load calculatoion on this service. Without relying just a little on the panel schedule someone would have to trace and verify each circuit and the reality is that will not happen. We aren't talking about adding a 50 amp load, just a 50 amp circuit.
Your absolutely correct Joe and its a shame people are either that lazy or reckless.

Heck, as long as we are making assumptions and cutting corners we may as well load up the service and see if the main trips out like that other guy suggested. Even his poor advice is better than guessing.
 
  #24  
Old 07-22-14, 10:28 AM
Justin Smith's Avatar
Member
Join Date: Dec 2010
Location: Cressona, Pa, USA
Posts: 2,546
Unless you have some serious heating or HVAC loads (such as a tankless water heater) you're most likely going to be fine. The RV is probably going to use less than 30A most of the time, anyway. The only heavy loads in them are the rooftop a/c units, and they're 120V anyway.
 
Reply

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


Thread Tools
Search this Thread
Display Modes
'