DIY Home Improvement Forum banner

1 - 19 of 19 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
In a large bunkhouse we need to add a second range, water heater, and kitchen outlets. The existing panel is 125 AMP (with breaker), and don't want to redo entire panel. A consultant said to install a 200 AMP drop, with a panel to handle the additional load. Would you then feed each of the panels from that drop as main panels, or use a new 200 AMP panel as the main, and the 125 as a sub-panel from that? I assume in either instance, the grounding would be done as a 200 AMP service. Just realized if each was a main panel, the new one couldn't exceed 75 Amps, or total would be over 200. Any other ideas appreciated.
 

·
Banned
Joined
·
17,158 Posts
Hmmn, let me guess, 30 or 40 amp for the existing stove, and now needing another 30, no lets just make them both 40 amps for sake of easy for the stoves. That right there takes 80 amps from the 125, which leaves you 45 amps avail. Take another 30 amps for the water heater, unless you already have one there already, so that would mean you have already used 70 amps on the existing 125 amp panel, add another 70 amps, that makes it 140 amps. Lights that are already there would mean 15 amps, outlets would mean 20 amps, so that means you are already up to 175, add the new 20 amp circuit, that takes you up to 195 amps.

That would leave you just 5 amps avail. for breathing room on a 200 amp service, and over 70 amps on a 125 amp panel. Sounds like you need to think this endevour over a little longer and consult with a electrician or company in your area, than trusting some random web forum.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #4
Hmmn, let me guess, 30 or 40 amp for the existing stove, and now needing another 30, no lets just make them both 40 amps for sake of easy for the stoves. That right there takes 80 amps from the 125, which leaves you 45 amps avail. Take another 30 amps for the water heater, unless you already have one there already, so that would mean you have already used 70 amps on the existing 125 amp panel, add another 70 amps, that makes it 140 amps. Lights that are already there would mean 15 amps, outlets would mean 20 amps, so that means you are already up to 175, add the new 20 amp circuit, that takes you up to 195 amps.

That would leave you just 5 amps avail. for breathing room on a 200 amp service, and over 70 amps on a 125 amp panel. Sounds like you need to think this endevour over a little longer and consult with a electrician or company in your area, than trusting some random web forum.
I agree totally, the consultant was from the local electric company, and the owner is paying for the "upgrade" so what the man says is "gospel".
 

·
Super Moderator
Joined
·
9,096 Posts
I agree totally, the consultant was from the local electric company, and the owner is paying for the "upgrade" so what the man says is "gospel".
Who is doing the upgrade?

If this is not your home, we can't help you.
 
  • Like
Reactions: Speedy Petey

·
Registered
Joined
·
5 Posts
Discussion Starter #6
Campground employees, the electric company said is OK if inspected. I have (40 years ago) experience in residential service, so I am the "expert".
 

·
Registered
Joined
·
50 Posts
Don't think that is the way it works when figuring loads, you can have many more breakers adding up to way over your 200 amp service. If you look at most modern breaker panels there are 400-500 amps of breakers or more. You need to do a load calc to see what is going to be used all at once. I believe I saw a post on load calcs on here where one of the Pro Electricians said a panel might have 850 amps worth of breakers on it and not be overloaded.
 

·
Banned
Joined
·
17,158 Posts
Don't think that is the way it works when figuring loads, you can have many more breakers adding up to way over your 200 amp service. If you look at most modern breaker panels there are 400-500 amps of breakers or more. You need to do a load calc to see what is going to be used all at once. I believe I saw a post on load calcs on here where one of the Pro Electricians said a panel might have 850 amps worth of breakers on it and not be overloaded.
Usuaully with A/C units, Furnaces, Electric Stoves, Water Heaters, pumps, you can go by the breaker size, since the Peak current load will be the max breaker size, medium load, or continuous is usually within 10 amps of max. It is easier on those types of loads to go by the breaker size in the panel. Anything else like lights and outlets, you can't, due to you may only be at any given time be using maybe 1/2 a amp, or could be loading with 5 amps continuous. Which is why you have to do a load calc' to get those proper loads.

With the OP, they just do not have enough service for what they are planning on adding into the existing panel.
 

·
Master Electrician
Joined
·
1,165 Posts
you've got lots of room on the amperage, The odds of everything being on at the same time are slim to none. It's why they have load calcs. If a 200A service i sufficient for a house with an oven and baseboard heating i'm sure it'll hold up to your two kitchen scenario. Google "residential load calculation" and download the file from the second link if your interested in doing a quick calculation to nip any doubts in the bud.
 

·
Lic Electrical Inspector
Joined
·
1,843 Posts
Amazingglazier said:
Just looked I have 565 of breakers in my 200 amp main and 160 in my sub
The sum of the branch circuit breaker ampacities has nothing to do with the size of the service. Service size is based on the calculated load. The calculated load is done using demand factors. Demand factors are a result of decades of data the Poco's monitor from millions of all types of homes. I order to properly help you, we need the nameplate ratings of a the appliances fastened in place plus the square footage of the building.

To give you an example, a 12 KW (12,000 watt) range has a demand factor of 8KW. So even though the range has a nameplate rating of 50 amps, only 33 amps is used for sizing the service. The online calculators take all this into consideration. Or you can try to do it the way we professional electricians do it. With a calculator, pencil and a code book.

Good luck!
 

·
Licensed Electrical Cont.
Joined
·
7,829 Posts
Campground employees, the electric company said is OK if inspected. I have (40 years ago) experience in residential service, so I am the "expert".
Unless your 5 years old you could not had many years experience 40 years ago.
What is your level of expertise.
Also, CAMPGROUND EMPLOYEES??? THAT is who is going to be doing the work? With you supervising??


WHY is it that places like campgrounds, where hundreds of people, mostly children, will be is where folks like to cut corners and cheap out.
Tell the cheap a$$ owners to hire a proper electrician to do this job correctly and safely!
 

·
Registered
Joined
·
5 Posts
Discussion Starter #15
OK posted and lost it try again. My experience doing residential services was 4 years in my early twenties I am now 68, and retired from the commercial fire alarm industry (which when I started was high voltage) , so I am not a total novice, just somewhat dated in the high voltage side. I work camp to augment my retirement, and get to travel the country. The owners here are very concerned about safety, they bought the campground complete with inadequate, improperly done wiring, and have spent thousands in total rewire of the campground by professionals. The bunkhouse was not a part of that project in that on the surface it "looked OK", and is remote from the campground proper. What started as a simple "fix it" after I discovered outlets with no grounds while installing GFI receptacles, has grown into an almost total re-wire as each item looked at uncovered more violations. The service drop idea got started when I discovered that the the main breaker in the bunkhouse was fed with 2/0, it starts in another building on a 50 Amp breaker fed with 8 Ga well wire. Thereby the decision that a new service drop was a must. The electric company field engineer said the transformer 400 ft away was adequate for the load, and recommended using 4/0 because of the distance. But he felt that the load center bus was stretched beyond its limit by the potential load and suggested a second load center for just the kitchen. As far as load calculations, with a range, a cooktop and electric water heater it don't seem too bad. But the potential for unexpected load in a 30 person bunkhouse is incalculable. There is already two toasters, 2 microwaves, 2 refrigerators, 2 coffee makers, 3 space heaters, an electric grill, and a roaster oven. People frequently will bring there own appliances, then there is the possibility of multiple hair dryers, curling irons, etc. The kitchen did have a gas range and there was a gas fireplace and water heater. The owner is afraid of gas (fire, explosion, CO) and removed/took these items out of service. My original question was how to properly connect two service panels to a new underground feed, not why it was needed (or not). Since this is a DIY forum, I understand your reluctance to help, but why critisize what you don't know the details of?
 

·
Licensed Electrical Cont.
Joined
·
7,829 Posts
My original question was how to properly connect two service panels to a new underground feed, not why it was needed (or not). Since this is a DIY forum, I understand your reluctance to help, but why critisize what you don't know the details of?
Which is why I asked what the details were. Many people like to leave out details when it benefits them, such as this case.
I am in no position to, nor do I choose to, help anyone in a situation like yours. This is a job for a professional, period. I am sure others don't care, but I do, which is why I make choices such as this.

DIY stands for "Do it yourself"...FOR YOURSELF.

Good luck to you, and good luck to your bosses and the campers as well.
 

·
Master Electrician
Joined
·
1,165 Posts
Not that i begrudge anyone capable of doing their own work but i'm curious as to how it works in the U.S. Here a place such as that would have to get a permit to do the work. If the utility is required to come and disconnect anything a permit has to be issued with a person/company with a masters license and a contractors license(with insurance). Now a homeowner can do their own work but the inspectors grill them to make sure they didn't just say they did it and hire it out. If the utility isn't required they could in theory do the work without a permit but if something ever happened and their insurance found out any claims would be null and void at that point. If you all don't want to clutter up the thread please PM if you know the rules for this cross border.

In my opinion if the rules are similar all talk of competency aside it's just not worth the legal risk involved.
 

·
Super Moderator
Joined
·
9,096 Posts
Andrew, that depends on the area you live in.
Each state makes its own rules about being licensed and insured.

Where I live, you have to have a license to contract work, but not to work as an electrician.
 
  • Like
Reactions: andrew79

·
Registered
Joined
·
779 Posts
The sum of the branch circuit breaker ampacities has nothing to do with the size of the service. Service size is based on the calculated load. The calculated load is done using demand factors. Demand factors are a result of decades of data the Poco's monitor from millions of all types of homes. I order to properly help you, we need the nameplate ratings of a the appliances fastened in place plus the square footage of the building.

To give you an example, a 12 KW (12,000 watt) range has a demand factor of 8KW. So even though the range has a nameplate rating of 50 amps, only 33 amps is used for sizing the service. The online calculators take all this into consideration. Or you can try to do it the way we professional electricians do it. With a calculator, pencil and a code book.

Good luck!
what this guy said. lots of demand factor rules in the code. say this kitchen had four 12 kw ranges. total for all four ranges is only 17 kw from a service sizing standpoint. idea is that what is the likelihood that all four ranges in a residential kitchen would be running at the same time. now if we are talking about electric clothes dryers, the rules are different. load for these is 5 kw or the nameplate, whichever is greater. demand factor is 100% for the first four clothes dryers. another example is lighting. load is calculated at 3 VA per square foot for dwelling units but only the first 3000 sq ft gets a demand factor of 100%. up to the next 120,000 sq ft, demand factor is only 35% for lighting. lots of rules here.

note that these demand factor rules discussed here are for sizing services. for the individual loads, conductor size and OPD size is dictated by the equipment regardless of demand factor. using this 12 kw range example, an 8 kw maximum demand doesn't mean you can size your breaker and branch circuit conductor for 8 kw.
 
1 - 19 of 19 Posts
Top