Anyone upgraded incoming power service?

[atgcpaul]

This house we're buying has a 200A service. After doing some math for
continuous current draw in the shop, here's what I have:

20A, 220V for new table saw
15A for lights
15A for AC/heating
12A, 220V for dust collection


That's 62Amps I need in the shop with all these things running. So I'll probably
have a 100A subpanel in the shop so I can have a 20A "appliance" circuit to
plug in misc smaller tools like drills, planers, routers, etc.

Will a typical 4bdrm house with only 2 people living in it, need more than 100A? Gas heat/gas water.

Otherwise, it looks like I'll have to get my service upgraded to 250A or 300A.
Is this something the electric company does without a big hassle or expense?
The service coming into the house is underground but there are utility poles
on the sidewalk. Could they run 100A service overhead to the detached
shop only? (Local laws apply, of course)

Thanks,
Paul

[Ken Massingale]

Paul,
I don't think those items pull those amps when running. My Ridgid TS wired for 220 draws 3 amps per leg running, a large AC (window) unit draws 3-4 amps and 9, 4 ft. light fixtures are less than 5 amps. The HF 2hp DC pulls around 7 amps at 110 volt, but I'm gonna rewire that for 220 to cut the ampere load. Your amps sound like the breaker ratings.
Our house is somewhat over 2,000 sq. ft, kinda small, with 2 of us, gas heat and water and range. We have a 200 amp service with a 60 amp service to the shop from that panel. The only issue I have is that I need to run 100 amp to the shop instead of the 60 I have.

[LCHIEN]

Paul,
I don't think those items pull those amps when running. My Ridgid TS wired for 220 draws 3 amps per leg running, a large AC (window) unit draws 3-4 amps and 9, 4 ft. light fixtures are less than 5 amps. The HF 2hp DC pulls around 7 amps at 110 volt, but I'm gonna rewire that for 220 to cut the ampere load. Your amps sound like the breaker ratings.
Our house is somewhat over 2,000 sq. ft, kinda small, with 2 of us, gas heat and water and range. We have a 200 amp service with a 60 amp service to the shop from that panel. The only issue I have is that I need to run 100 amp to the shop instead of the 60 I have.

Ken, if your HF 2HP DC is only pulling 7A then you must have that thing choked way off because if the air flow is restricted the amps go down accordingly. My HF DC pulls 14.7 Amps with the inlet wide open which is what it should do.

Paul, Ken is right that all the values you list are probably maximum and
and not all should be maxed out all the time. while you probably would use a 15A circuit for lights, 8, dual 40-watt fixtures (a lot of light) would draw 640 Watts or about 5 Amps. You also made a huge calculation error - you calculated 120V amps as if they were 220V amps, you simply added them up.
Two 120V circuits at 15 Amps each are NOT 30 amps to the subpanel.
it's just a single 15A 220V load.

so calculating load panel amps:
20A 220V for saw = 20A
15A 120V for lights & utility + 15A 120V for utility outlets = 15A
15A 220V for Ac/heat = 15A
12A 220V for DC =12 A

since i highly doubt that you will be pulling a full 20A on the table saw at the same time you will be using lots of utility circuit power
a 60A panel will likely be sufficient and 100A panel will surely be enough
w/o having to upgrade your house 200A service. One important question is, do you have central A/C - that could easily draw 40-50 amps by itself.

If it were for me I'd add a circuit for an air compressor.

[atgcpaul]

Paul,
I don't think those items pull those amps when running. My Ridgid TS wired for 220 draws 3 amps per leg running, a large AC (window) unit draws 3-4 amps and 9, 4 ft. light fixtures are less than 5 amps. The HF 2hp DC pulls around 7 amps at 110 volt, but I'm gonna rewire that for 220 to cut the ampere load. Your amps sound like the breaker ratings.
Our house is somewhat over 2,000 sq. ft, kinda small, with 2 of us, gas heat and water and range. We have a 200 amp service with a 60 amp service to the shop from that panel. The only issue I have is that I need to run 100 amp to the shop instead of the 60 I have.

Well, this is where my confusion and ignorance about electricity appears.
Those are the breaker ratings and what the manufacturers recommend
as dedicated circuits for the TS and dust collection. Grizzly 3hp TS and
Grizzly 2hp dust. Even though they may only use a fraction of what is
actually called for, don't they need to be on separate circuits and doesn't
that mean that that electricity is no longer available elsewhere? I suppose
all the lighting and AC could go on one 20A circuit. Breaker wise, doesn't
that put me at:

20A for saw (or is it 10A since it's 220V?)
15A for dust (or 7.5A?)
20A for AC/lights
20A etc

[Ken Massingale]

Loring, probably my feeble memory again
I'll check it in the morning and try to get it right.
ken

[atgcpaul]

Paul, Ken is right that all the values you list are probably maximum and
and not all should be maxed out all the time. while you probably would use a 15A circuit for lights, 8, dual 40-watt fixtures (a lot of light) would draw 640 Watts or about 5 Amps. You also made a huge calculation error - you calculated 120V amps as if they were 220V amps, you simply added them up.
Two 120V circuits at 15 Amps each are NOT 30 amps to the subpanel.
it's just a single 15A 220V load.

so calculating load panel amps:
20A 220V for saw = 20A
15A 120V for lights & utility + 15A 120V for utility outlets = 15A
15A 220V for Ac/heat = 20A
12A 220V for DC =12 A

since i highly doubt that you will be pulling a full 20A on the table saw at the same time you will be using lots of utility circuit power
a 60A panel will likely be sufficient and 100A panel will surely be enough
w/o having to upgrade your house 200A service. One important question is, do you have central A/C - that could easily draw 40-50 amps by itself.

If it were for me I'd add a circuit for an air compressor.

Good thing I'm getting an electrician to do this, huh? The house has central
AC. The garage/shop is unattached. Curious, how does 20A 220V for saw
equal 20A AND 15A 220V for AC/heat also equal 20A? Typo, right? For
AC/heat, I was thinking of just going with a window unit for AC and maybe
propane heat in the winter. That should cut the load down to 15A 120V or
7.5A, right? Thanks for your help guys. It seems I won't be in for a major
overhaul afterall.

Paul

[JR]

Current analogy

Paul, it's not too hard to understand the basic idea of how household current works. It's sort of like the volume of water a river and its tributaries can handle.

Say the Ohio River at Pittsburg has 1000 gallons per minute capacity. That means both the Allegheny and Monongahela can be running at 500 gpm. However, either of those rivers might have an individual capacity of 750 gpm. The can't both be running at 750, but one of them can do that at any given time, leaving the other to run at up to 250. If the total is over 1000, the Ohio floods - it blows a fuse.

If you have a 60 amp service box, the most you can run through its main breaker at any given time is 60 amps. That might sound like four 15-amp subordinate breakers, but you could easily configure it with five or six breakers, assuming they would not all be running at maximum at any given moment.

A fact worth noting is that a 110/220v motor uses half the current (amerage) at 220 compared to 110. So if it's six amps at 110, it's 3 amps at 220.

Not too many tools use more than 10 amps (I say without knowing the real facts as to the entire power tool universe!). DCs, as Loring noted, are power hogs, and should be on their own breaker. A big table saw might be in the same boat. Most other tools are a fraction of that.

HTH,
JR

[gsmittle]

JR, that's about the best explanation I've ever read. It took me a looooooong time to get my head wrapped around the amps/voltage relationship.

On a similar note, I had an electrician out here yesterday giving an estimate for my new shop. I wanted 100 amps, but the elec guy says I can get by with 60, since the major amp-pullers will be the DC and TS.

I dunno. I think I'll insist on 100.

g.

[LCHIEN]

Good thing I'm getting an electrician to do this, huh? The house has central
AC. The garage/shop is unattached. Curious, how does 20A 220V for saw
equal 20A AND 15A 220V for AC/heat also equal 20A? Typo, right? For
AC/heat, I was thinking of just going with a window unit for AC and maybe
propane heat in the winter. That should cut the load down to 15A 120V or
7.5A, right? Thanks for your help guys. It seems I won't be in for a major
overhaul afterall.

Paul

yeah typo,
the point is with 220V service, 20 Amps used come from both legs.
With 110 on 220V service, you can get say 15A from only one leg and you can get 15A from the other leg so two 15 Amp circuits only take 15A from the panel input.
therefore
20A @ 220 and 2 properly wired 110V 15A circuits would only require a max of 35Amps from the panel.
Note, both 110 circuits don't have to use the same no. of amps, the difference returns int he neutral wire, it's OK.

[Stick]

Yeah, we in the electrical utility industry use the water analogy all the time to explain things to tourists and such. The really dreaded question is when they ask what Vars (volt amps reactive) are. And just be glad houses aren't 3 phase. That complicates things even more.

[JR]

Yeah, we in the electrical utility industry use the water analogy all the time to explain things to tourists and such.

Just as I was feeling miffed that my inspirational analogy was already being used, I realized that if pressed for an explanation for 3-phase I'd have to get a coughing fit and leave the room.

JR

[LCHIEN]

Just as I was feeling miffed that my inspirational analogy was already being used, I realized that if pressed for an explanation for 3-phase I'd have to get a coughing fit and leave the room.

JR

Thats where I mumble something about phasors and then leave the room.

Dave Barry the humor columnist, once explained electricity.

Ah, here's the text:

What is Electricity?
By Dave Barry

--------------------------------------------------------------------------------

What in the world is electricity?

And where does it go after it leaves the toaster?

Here is a simple experiment that will teach you an important electrical lesson: On a cool, dry day, scuff your feet along a carpet, then reach your hand into a friend's mouth and touch one of his dental fillings. Did you notice how your friend twitched violently and cried out in pain? This teaches us that electricity can be a very powerful force, but we must never use it to hurt others unless we need to learn an important electrical lesson.

It also teaches us how an electrical circuit works. When you scuffed your feet, you picked up batches of "electrons," which are very small objects that carpet manufacturers weave into carpets so they will attract dirt. The electrons travel through your bloodstream and collect in your finger, where they form a spark that leaps to your friend's filling, then travels down to his feet and back into the carpet, thus completing the circuit.

Amazing Electronic Fact: If you scuffed your feet long enough without touching anything, you would build up so many electrons that your finger would explode! But this is nothing to worry about unless you have carpeting.

Although we modern persons tend to take our electric lights, radios, mixers, etc. for granted, hundreds of years ago people did not have any of these things, which is just as well because there was no place to plug them in. Then along came the first Electrical Pioneer, Benjamin Franklin, who flew a kite in a lightning storm and received a serious electrical shock. This proved that lightning was powered by the same force as carpets, but it also damaged Franklin's brain so severely that he started speaking only in incomprehensible maxims, such as "A penny saved is a penny earned." Eventually he had to be given a job running the post office.

After Franklin came a herd of Electrical Pioneers whose names have become part of our electrical terminology: Myron Volt, Mary Louise Amp, James Watt, Bob Transformer, etc. These pioneers conducted many important electrical experiments. For example, in 1780 Luigi Galvani discovered (this is the truth) that when he attached two different kinds of metal to the leg of a frog, an electrical current developed and the frog's leg kicked, even though it was no longer attached to the frog, which was dead anyway. Galvani's discovery led to enormous advances in the field of amphibian medicine. Today, skilled veterinary surgeons can take a frog that has been seriously injured or killed, implant pieces of metal in its muscles, and watch it hop back into the pond just like a normal frog, except for the fact that it sinks like a stone.

But the greatest Electrical Pioneer of them all was Thomas Edison, who was a brilliant inventor despite the fact that he had little formal education and lived in New Jersey. Edison's first major invention in 1877, was the phonograph, which could soon be found in thousands of American homes, where it basically sat until 1923, when the record was invented. But Edison's greatest achievement came in 1879, when he invented the electric company. Edison's design was a brilliant adaptation of the simple electrical circuit: The electric company sends electricity through a wire to a customer, then immediately gets the electricity back through another wire, then (this is the brilliant part) sends it right back to the customer again.

This means that an electric company can sell a customer the same batch of electricity thousands of times a day and never get caught, since very few customer take the time to examine their electricity closely. In fact the last year any new electricity was generated in the United States was 1937; the electric companies have been merely re-selling it ever since, which is why they have so much free time to apply for rate increases.

Today, thanks to men like Edison and Franklin, and frogs like Galvani's, we receive almost unlimited benefits from electricity. For example, in the past decade scientists developed the laser, an electronic appliance so powerful that it can vaporize a bulldozer 2,000 yards away, yet so precise that doctors can use it to perform delicate operations to the human eyeball, provided they remember to change the power setting from "Vaporize Bulldozer" to "Delicate."

[Jeffrey Schronce]

This house we're buying has a 200A service. After doing some math for
continuous current draw in the shop, here's what I have:

20A, 220V for new table saw
15A for lights
15A for AC/heating
12A, 220V for dust collection


That's 62Amps I need in the shop with all these things running. So I'll probably
have a 100A subpanel in the shop so I can have a 20A "appliance" circuit to
plug in misc smaller tools like drills, planers, routers, etc.

Will a typical 4bdrm house with only 2 people living in it, need more than 100A? Gas heat/gas water.

Otherwise, it looks like I'll have to get my service upgraded to 250A or 300A.
Is this something the electric company does without a big hassle or expense?
The service coming into the house is underground but there are utility poles
on the sidewalk. Could they run 100A service overhead to the detached
shop only? (Local laws apply, of course)

Thanks,
Paul

Paul,
My home is 6 years old. It has 200 A service panel. In addition to our main house we have an attached in laws quarters. Dual zoning AC system, 3 full size fridges, 1 deep freeze, large screen tvs,multiple computers, tons of monitors, etc. We use about 2000 kwh per month right now.
My shop is detached and has 100A service from the main box. I have 220 50A for welder (that has been used once in 6 years), 220 20A for 8" Jointer, 20A dedicated for DC, 20A dedicated for TS, 15A for 4 sets of overhead lighting, and a couple 15 and 20 A for outlets. We have never had anytype of problem, even in the last week with extremely high heats, heavy AC and other electric utilization and the DC & Jointer (new toy) running all the time. I do not know all the techinical stuff the other folks do but I can tell you that with 200A in home and 100A subpanel in the shop you are going to be fine.

[LCHIEN]

Paul, it's certainly not dangerous to run your household with the existing 200A service if everything is properly done. the breakers are sized to protect the wiring from overheating.

If you find you are tripping breakers or are having other problems you can always upgrade the service later at the same cost as doing it now.

That reduces your problem to whether or not you want to put a 60 or 100A panel in the shop - I personally think a 60A panel should be plenty if done right. You might price the difference and make a decision.

[Jeffrey Schronce]

That reduces your problem to whether or not you want to put a 60 or 100A panel in the shop - I personally think a 60A panel should be plenty if done right. You might price the difference and make a decision.

Someone stated in another thread that 100A could possibly be the same cost right now as 60A is only availble in copper wiring, whereas 100A is avalible in a more cost effective conductive metal (I believe it was aluminum?). Breaker costs would be slightly higher. Labor should be the same.