Discuss Professional Engineer's answer to: My electric line comes from 2 separate wires at ...

my electric line comes from 2 separate wires at 115 120 volts each.can I install an electric heater for my house that nedds 23 000 kilowatts,the amperage is 100 thanks

As a registered engineer, I go with the answer above - get a licensed electrician.  Residential electricty comes typically as 120 / 240 single phase.  The information from Humble is not exactly correct.  Residential panels range from 125 Amps to 225 Amps (large luxury homes do have even larger ones then that).  These are not 100% load rated, so you can only run them continually at 80% of their rating.  There is a significant diversity, so if you total everything up it will exceed the rating of the panel.  If you overload the wire size, it will heat up and burn your home to the ground.  The fact that one lead was 115 volt and one was 120 volt indicates the 115 volt line is loaded to a point that your are experiencing voltage drop - not a good sign.

Do you have an existing electric heater?  Are you replacing it?  If so, the newer units are more efficient and draw less electricity. 

Go to your main box and look at the rating of the main breaker.  Take 80% of that and you have your existing capacity.  Do you have an electric oven or range?  They also draw significant amounts.  To save an unnecessary service call - measure your home and figure out the size (square footage).  Then make a list of all major electrical appliances - oven, water heater, heaters, stove, air conditioner, power tools in the garage, well pump, etc.  Get the rating in volts and amps from the main electrical breaker, number of smaller breakers, and the rating on the panel.  Go to the local home improvement center and they can give you a guess-ti-mate of whether you are in trouble or not.  If you are close to being overloaded, get an electrican to install a new panel.  If your electrical panel is over 20 years old, it may pay to upgrade since the electric heater is a major part of the typical home load. 

There are no problems - only unsurrmounted opportunities
Liked this answer? Tell your friends about it

6 Comments About This Answer

Add your comment
Humble Thinks this answer is Not Helpful:

If you were a professional engineer, you would know National Electrical Code.  You don't.

Professional Engineer

You are the one who does not know the code.  I regularly do forensic engineering on systems that have failed.  I have seen the results of failed systems.  The original description sounds like an older installation which may not have been installed per code.  The writer describes 2 wires as the service conductors = in other words probably an ungrounded system.  To connect to this system would be dangerous for an inexperienced worker.  There is a specific method of sizing the system.  I do not explain it in detail since it is very easy for a poorly trained person to get in big trouble.  By getting a generalized level of the size of service, the writer can then speak intelligently with the electrician.  Too many low end electricians in the residential market do not know the code and do not provide a safe system. 

You do realize that electricity is generated in 3 phases - each 120 degrees outof phase with the others.  A single phase system is really two of the three phases and are not 180 degrees apart.  Older systems are delta connections while newer ones are wye.  Mixing these systems can be very dangerous if you do not know what you are doing.  If your only exposure to electricity is an Ugly's Book, you are a long way from knowing how to design an electrical system.

Humble Thinks this answer is Not Helpful:

Suit yourself.  I am not going to get into a hassle with you.  But I have been twisting wires for thirty years now.  You haven't.

The Unknown Philosopher Thinks this answer is Not Helpful:

Humble, please realize that "Professional Engineer" is one of the false screen names of the most abominable atheist on AOL Answers, who posts under more than 200 names that I know of.


He will do absolutely anything to be obnoxious and boorish.  That is how much hate that miserable bigot has in him and how far he will always go to support atheism, death camps, and all the atheist atrocities that go with these barbarian obscenities.


Stick around on AOL Answers and you will see how obnoxious this devious old bigot really is.  One of his practices is to post anonymously, claim you are Rocmike, and accuse you of racism.


That is standard atheist sour grapes.  Be warned accordingly.

Anonymous Comment

Rocmike aka Anselmogx it is appearing more and more that Humble is one of your 60 or 70 aliases.

Anonymous Comment

The two phases coming into my house surely are 180 degrees out of phase. 120V to neutral, 240 between them = 180 degrees.

And you can easily generate this from any one phase with a center-tapped transformer.

PE? You sure?

Add Your Comment (or add your own answer)