electrical ??

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Most of the 60 amp services I've seen around here are only 110 volt ( single conductor and gnd). Is yours 220 volt feed? If so it should work fine. It is up to the power company to upgrade the feed if it isn't. You'll have to pay for them to make the connection though.
 
If you're main breaker is a 60 amp that is all that is the total available amps to however many panels you put in the house. If you have a 60 amp service wire drop but you change out the main breaker/ disconnect you will need to make sure that you do not exceed the capacity of the wire.... Bad things will happen
 
This is a question for your electrical utility. If you are considering a panel upgrade, you will need the power company to disconnect anyways and as they own the cable up to your weatherhead, (for overhead applications), they will likely insist on an upgrade as part of the permit. You will take a permit for this, right?
 
It.s not me with the issue. It was brought up in conversation. The debate was regarding the fire hazard of having 60 to the house and a 100 amp panel inside. I am looking for a understandable explanation of how this plays out safety wise. Electrical is not my field, but I found this rather interesting and would like a simple synopsis of this situation. I'm sure this is done all over, permitted or not. How does one tell from the outside what service they have coming in?
 
Im no elec by any means Martin, but I would think that it wouldnt be a fire hazard, if the house is fed 60A, thats all he is going to get period, no matter how big of a panel he puts in. The bigger panel allows for more circuits, but wont give more Amps....curious to see more replies.
 
Does the panel have a main breaker? If it does what size? 100 amps in the rating on the busbars. If you have a 100 main panel and you pull 100 amps on it in theory the 60 amp line from the utility would be overloaded/ heat up, but utilities have a different way of calculating their wire size. Usually you would need a 100amp service drop from the connection point of the utility. Down here what's bolted to your house is sized per the NEC code and the utility connects to it with what they want.
Hope this helps.
 
4spdragtop said:
if the house is fed 60A, thats all he is going to get period, no matter how big of a panel he puts in. The bigger panel allows for more circuits, but wont give more Amps....curious to see more replies.
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Actually electrical devices are not "fed" electricity, instead they "suck" a volume of electricity. If they were fed electricity, then all wiring on a circuit would have to be a larger minimum gauge.. think of an automotive fuse.

The limiting factor on the amp draw avail is always the gauge of the wire used. Breakers and fuses simply ensure that they fail before the wiring.

It is likely that the wiring from the pole to weatherhead can support 100a of draw, however, the code more than likely requires an upgraded mast (increased diameter pipe and increased wire size).

Remember, wire that cannot support the load on it is just a long fuse waiting to blow. If it happens in the wrong place, well, you can figure it out.

Grant
 
4spdragtop said:
if the house is fed 60A, thats all he is going to get period, no matter how big of a panel he puts in. .
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Sorry, not true. To reword OneOFmany's reply a little bit, one good example is trying to run a BIG load off a cheap too-small extension cord.

Ever done this, and had a cord/ the connectors get "a little warm"? The same condition applies to the too-small service drop.

The SAFE current that can be used is limited by the wire size, and just as bad, too-small wire causes VOLTAGE DROP, and the longer the run of wire, wherever it may be, causes more and more drop, and more and more HEAT

Let's say you have no fuses/ breakers from the pole to the main 100A breaker, but let's make it even WORSE. Let's say you have a 150A breaker. This is big enough to allow more than a 200 % overload, IE over 120 A, or 2 X 60.

Let's say you DO have a "bunch of stuff", Ma is drying clothes, cooking a big roast, cooking a large meal, you have an electric furnace, big electric heater in the shop, and welding some 3/4" material. Maybe you have a well pump, etc.

If we haven't got to 120-more amps yet, we probably passed it a long time ago.

Two things are going to happen:

ONE the high current on the too-small service wire is going to cause heating, and if it's a hot summer day, the only thing that cools the drop (if overhead) is airflow. This cooling is lessened on a hot day This heating is concentrated at a marginal connection, like where the drop wire connects in the box, and IF these connections start to heat, repeated heating/ cooling thermal cycles causes these connections to loosen. Then it can REALLY make heat, can you spell fire?

NOTE In ANY electrical system, it's wise to periodically inspect and tighten connections. Use your skill level as a guide, or hire a pro. ALUMINUM service wire is especially vulnerable, because it "flows" over time and becomes loose.

TWO The too-small drop is just like the undersized extension cord. It has resistance, (you can look up resistance / 100 ft for various copper/ aluminum wire) and calculate just what that drop would be.

Low voltage CAN be VERY hard on some equipment. Heaters, Ranges, etc, "don't care" but large motors do. Your nice big 3-8hp air compressor motor HATES low voltage. So does some electronics/ TV sets, etc.

Worse, the switching on/ off of large loads causes voltage "surges" as the voltage changes under load. MANY electronics devices REALLY hate this

The house I grew up in only had 60/80A cartridge fuse protection at the meter disconnect, and occasionally we'd lose one. Dad would be welding, Mom would not notice and put something in the dryer, the (then coal) stoker would fire up, and maybe the water pump, and maybe the washer was running.

If something didn't blow in the main box, the disconnect would go -----

I learned at a very young age (about 12-14) how to safely change cartridge fuses.
 
I will stand by my original post but I want to clear a couple of things up that have been posted since. I am a licensed electrician with 15 years experience so I do know what I am talking about.
First, the limiting factor for available current will be the breaker or other current limiting device. The wire size should be matched to the overcurrent device but it will run a higher amperage thru to a point of failure if not properly protected
Second, aluminum wire doesn't "flow" to create the hazard. What happens is as amperage flows thru the wire it heats up and cools down which in turn causes it to expand and contract. It does this at a much greater rate than copper wire does which is why it is important to periodically check the tightness of the connections
Last, if you stack a 100 amp breaker after a 60 you just wasted some cash because the total available is still only 60 amps

You guys can probably all school me on a bodies but this is
My career and I finally get a chance to contribute some good knowledge
 
I defer to your experience.

What I was simply trying to state was:

1) Electricity is drawn by a device, and the amount of amps the wire/breaker/fuse will "flow" at a given time is dependent on the device's requirements at that time. It is a common misconception that the electricity "pushes" the same volume to every device on the circuit. As 67Dart273 pointed out, this is why a small 110v 2a LED only requires a thin wire compared to a 110v 20a kitchen receptacle which requires a 12g. The device determines it.

2) Although you are correct that the breaker is "normally" supposed to be the limiting factor, it is often the wiring which can be the limiting factor. A perfect example is using a cheap inside extension cord on a device that normally requires a high amperage flow (example 1500w 110v heater), where the often 16 to 18g wire of the cord cannot safely support the current flow (80% rule) that a 15a breaker provides. In this case, the wire can and often does fail causing fires.

3) I dont think the question was about putting a 100a breaker behind a 60a, but was in reference to changing the main breaker itself. There is no load limiter on the pole which prevents 100a being drawn from the pole. But the wiring from the pole to the main breaker has to be rated to carry it (electric co's responsibility), and more importantly, the mast on the house (from the electric co. connectors to the main panel often need their wiring upgraded and the thickness of the mast piping as well.

For example, I upgraded my main service from 100a to 200a, and in my case, our electric co. did not have to change their service. I of course did, and rebuilt a new mast.

Grant
 
As an electrical engineer employed in the business of designing these I would attempt to offer some guidance on a level all can understand. Technically the circuit breakers installed anywhere are required to protect the wire on their output and generally do not do anything to protect the "input" wiring. The wire coming to the house or panel in this situation would be protected by the Utility at their connection, and it is likely that the utility transformer will not support more that the wire since to do so places resources in a place where the utility cannot benefit financially, which is what they do. That being said, in the US the service entrance wiring, technical term for the incoming wires, is generally owned and installed by the client, not the utility. An electrical inspector should be involved in any change of service and should disallow such an installation and the utility would be expected to require you to upgrade it as well. Most local utilities will not connect to less than 200 amps of wire, so a 60 amp feed must be an old one and should be upgraded to match the "load" as represented by the circuit breaker. I would be happy to address specific concerns based on detailed information such as what is the wire size etc, PM me if interested. A little sketch of the situation goes a long ways, after we are pretty much all picture freaks here anyway!
 
It's pretty clear that adding a 100A panel to a 60A service feed will not magically give you an extra 40A capacity, but the original question relates to potential fire hazard and there may be a circumstance that could cause such a hazard. As stated, the utilities will not normally provide a 60A service these days as 100A or greater is the norm and the utilities own the cable up to the mast in most circumstances. Suppose an existing 60A service was replaced by the electrical company. Since the modern norm is 100A or higher, the protection at the pole and the gauge of wire from the utility is 100A spec'd. This would not be a problem feeding a 60A service as the load expected is lower than the rating of the service feed. Now suppose the homeowner upgrades to a 100A panel in the house. What is left of the original 60A installation is the meter socket and mast wire. Now you have a service feed capable of delivering 100A, a house panel with a 100A main breaker, and mast/meter wiring capable of supporting 60A. Since all the protection is 100A, you could overload the mast/meter wiring, possibly creating a fire hazard. This is why I was so adamant about taking the proper permits for this sort of work.
 
I just love learning something new everyday.

So we have cleared the air about the hazzards of having incorrect wiring, but if there is a 100amp panel inside the house, how does one tell at the mast what is coming from the mast in, assuming the electrical company is providing 100 amp service to the mast? or even 60 amp service to the mast?
 
Assuming as you said that the electric co. has the correct gauge wiring to supply 100a service to your masthead.

Please understand, by putting a 100a main breaker on your panel, you are allowing 100a of current to be drawn before tripping the main, regardless of what your mast is. To determine if the mast is correct, you need to ensure that a) the wiring inside is of the right gauge (both power and bare ground). b) that the mast is of sufficient diameter to support those wires (for bending). This information can be found in your local electrical code.

Grant
 
plumcrazy704406 said:
I just love learning something new everyday.

So we have cleared the air about the hazzards of having incorrect wiring, but if there is a 100amp panel inside the house, how does one tell at the mast what is coming from the mast in, assuming the electrical company is providing 100 amp service to the mast? or even 60 amp service to the mast?
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You have to assume the electric utility would NOT have been so stupid as to hook larger service to a smaller masthead, but I guess it's possible, and certainly possible that someone DID change a panel without proper permits/ inspections, so you really cannot tell by the panel.

I'd say in that case, if there's any question, call the power co. and get someone out, or an electrician and get it inspected.
 
67Dart273 said:
You have to assume the electric utility would NOT have been so stupid as to hook larger service to a smaller masthead, but I guess it's possible,
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This is actually true very often. Most electrical hookups in our city can easily support 100a to the mast, but when the home was built, because 100a was not the norm, homebuilders often cheaped out on 60a service from their end.

Last summer, I helped my brother change his 100a panel to a 200a on a two year old house. The electric service was fine to the mast for 200a, but the home builder saved a few $$ and used too small a pipe/hole and a 100a panel. I had to change mast as well as panel. Most houses in his sub are using 100a masts/panels.

So, IF the owner simply changed the panel with no permits (and no electrical co. disconnect - silly but possible) then the mast may be incorrect. By looking at the feeds to the main breaker, you should be able to determine the wire size. Use a visual measure, and compare the gauge to a display at your local big box store.

And yes, I pull permits :)

Grant
 
67Dart273 said:
You have to assume the electric utility would NOT have been so stupid as to hook larger service to a smaller masthead,

.
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It's common practice for service drops to be a minimum of 2/0, (200A), regardless of what type of smaller service you request. Keep in mind the conductor sizes specified in NEC are minimum. There is no maximum size specified.

NEC article 220 and 230 provide full info on service drops and conductor size. It's tough to find direct prints of the NEC on the net, but here's an interesting article on service entrances.

http://ecmweb.com/nec/code-basics/understanding_conductor_requirements_0301/

Beat me to it by 9 minutes Grant!
 
plumcrazy704406 said:
Electrical is not my field, but I found this rather interesting and would like a simple synopsis of this situation.
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I have never wired up a breaker panel, but I work with electricity daily. As long as the mains breaker is rated for the 60 amps, you will have no problems. A simple comparison would be a surge strip with lets say 10 outlets. If each outlet is rated at 15 amps, some might think that you can draw 150 amps from the strip. That isn't the case, because the surge strip would either have a 15 or 20 amp circuit breaker. You would even have a backup to the circuit breaker in the power strip with the circuit breaker in your panel. You are limited in your current draw by the size of your circuit breaker. I hope that this helps.

Craig
 
So how would a green horn tell from the outside of the house? The mast diameter? Or you need to be inside and see the main feed coming in?
How can you tell quickly what service it really is if your not an electrician?
The answers are appreciated.
:coffee2:
 
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