Upgrading 100A to 200A?

Are you comfortable with electricity? It can be done, but it is not really a DIY kinda job. It can KILL you.

Might talk to an electrician, since you asked here, tells me you are not comfortable with the procedure.

I replaced my service from 100A to 200A, but had to replace the main CB panel. Also had to get a new 200A service with disconnect. Also ran 200' of 3" conduit to the pole.

Cost me about $700 for everything.

Was with out power for about four hours.

Power company discoed wire, than ran new wire in the 3" conduit I buried.

Make sure you pull a permit!

This is probably not a DIY thing but if you can put the 200 back to back with your existing 100a it should not really be that expensive to have it done. Your existing wiring should not have to be disturbed at all. They just have to separate the neutral and ground bus and run another wire through the wall.

Why?

Have you ever blown a main fuse or breaker?

The utility won't change your street transformer or wiring into your house.

You will only increase the number of breaker positions in your panel, if you go to a larger count. This can be done with pony panels on your existing panel, also.

Increase your circuit wiring, as desired, leave some slack for a potential panel change and then see if you ever blow a main overcurrent device, or overload your meter.

Run it all and go clock your meter disk (assuming you have one) or LED.

Power (Watts) = revs (or pulses) x kH (see nameplate) x 3600 / time (do about 60sec worth)

From the power figure you get, above , divide it by about 230volts and see what current you get. If it's over 60-70 amperes, then worry.

RogerN

No, but I'm wanting to run maybe 100A to my utility room for my hobbies, and hopefully later to a shop building if I can afford to get one.

I have a home machine shop at my other house and am wanting to start moving stuff here. For right now I move it as I need it but if I get a building I hope to get it all from my old home shop to my current residence.

Right now I'm trying to do some auto body work/rust repair so I'm wanting to get power ran for my air compressor and welders. So far I've been able to get by running everything from my dryer power but I can't run too much at one time. I have a CNC lathe with a 7.5HP spindle motor and 2ea 1.25Hp servo axis drives. Then there is the 3Hp 230V air compressor and a 230V mig welder. I expect there could be some problem if I try to power my 400A TIG welder since it's rated for some 90A at 230VAC, then there is the stick welder that needs a 50A circuit. So, my idea was to run a sufficient circuit to my utility room (60A should do).

Anyway, if I can upgrade to 200A, (100A for house, 100A for shop) without rewiring my house that's what I'd be interested in doing.

RogerN

I'm pretty comfortable with electricity, I work with 480 3-phase on a daily basis. My problem isn't so much how to do it electrically as it is to do it to the satisfaction of the power company. At work we are considered electrical technicians, we don't do much running conduit but we repair the equipment when there is a problem. This can range from a problem with a 20 millivolt load cell signal or a problem with the 4160V going to our

2000HP-3000HP drives.

I'm not familiar with what is available to give me 200A in and be able to split it up to 2 or 3 100A feeds.

Thanks for the info.

RogerN

I've done this once, it was a big job but in this case it was going from a decrepit heavily overloaded 100A fuse panel (I'm actually amazed the house hadn't burned down) to a modern 200A breaker panel.

The house had overhead service so I had to install a new larger mast and replace the meter box. Additionally, I had to upgrade the grounding system to comply with current codes which involved driving two new ground rods. The job cost about $500 including the necessary permit and supplies, and the house was without power for several days until I had completed and had it inspected.

Underground power would have been much easier as the utility handles everything up to the meter box for underground or the weatherhead for overhead. Most underground installations have the meter box directly on the other side of the wall where the panel is so there is FAR less screwing around. Either way if you intend to do this yourself, read up on it, talk to your local inspector about any special regulations in your area, and gather all the parts you will need before you start.

100A is woefully inadequate for most modern homes. There is a good chance that like most houses, his was built with an undersized panel that was nearly full right from the start. Start adding new dedicated circuits for high amp loads like his air compressor and welder and such and you can really quickly end up with a full panel. Not to mention upgrading to a modern panel will get you AFCIs and other modern safety features. Also your calculation ignores power factor, there is a good chance that the amperage is much higher than you get calulating from the Wattage.

Thanks, I'm still planning on 100A for my home but I would like to wire some welder outlets and dedicate circuits for my machines. I'm not sure what the outdoor box would be called, is it just an outdoor breaker box with a few larger breakers? Or do they have a special name (distribution panel?) that I should look for? So far I haven't seen much as far as boxes that handle

100A breakers.

Would I just use a 200A main and run power to 100A panels or should each branch exit a 100A breaker and enter a 100A main in the 100A breaker box. I don't like the idea of running a 100A wire out of a 200A box unless it's on its own 100A protected circuit.

RogerN

Correct about the pf. I partially forgot and partially did not want to complicate things. Seeing he is an elect tech he could have handled it...LOL

What is "wattage"?

This large welder will give him a problem anyway. The impedance of the system will typically be too high to operate the welder properly, anyway. I have seen this before.

The utility won't change the wiring or street transformer and he ends up with the same ampacity, anyway. For circuit count and/or upgrade purposes the 200 distribution box would bea good idea but you really have to weigh out the pros and cons of the outcome before you jump into a project of that size.

100A is woefully inadequate for most modern homes. There is a good chance that like most houses, his was built with an undersized panel that was nearly full right from the start. Start adding new dedicated circuits for high amp loads like his air compressor and welder and such and you can really quickly end up with a full panel. Not to mention upgrading to a modern panel will get you AFCIs and other modern safety features. Also your calculation ignores power factor, there is a good chance that the amperage is much higher than you get calulating from the Wattage.

Josepi wrote:

Also, talk to your local utility about the incoming wire capacity. We only ran two sizes of conductor and that was based on the distance of the meter from the transformer.

The welders may give you trouble with the impedance of the incoming wire. We also had welding load billing penalties, that you cannot afford, due to regulations that allow utility bill compensation for loads that don't pick up properly on a meter. I doubt they could apply that to a residential service, unless they reclassify you.

YMMV

The house had overhead service so I had to install a new larger mast and replace the meter box. Additionally, I had to upgrade the grounding system to comply with current codes which involved driving two new ground rods. The job cost about $500 including the necessary permit and supplies, and the house was without power for several days until I had completed and had it inspected.

Underground power would have been much easier as the utility handles everything up to the meter box for underground or the weatherhead for overhead. Most underground installations have the meter box directly on the other side of the wall where the panel is so there is FAR less screwing around. Either way if you intend to do this yourself, read up on it, talk to your local inspector about any special regulations in your area, and gather all the parts you will need before you start.

RogerN wrote:

You could use a load center that is rated for outdoor use with a 200A main breaker. It needs to be rated for use as a service disconnect. You could look, for instance, at the Square D online catalog. I would rather put the 200A panel inside next to the 100A one - run the service wires a little to the side on the outside.

You would also replace all of the existing service wire and probably the meter enclosure. You can use smaller wire for a residential service than normal - you shouldn't do that for your usage. There are a number of requirements unique to services - read up or talk to people who know. Advice on the scene from someone who is competent would help a lot. Go through your plans with the inspector.

You should be able to do the swap.

The Permit thing, my county had a test, which if passed, you can pull your own permit.

The power company would not do anything here, except being notified from the county that the permit was issued. Next was to schedule the power company to pull the meter, and re-attach it. They said it could take two days, but they were able to come back that afternoon.

I was required to have a disconnect at the meter for safety purposes. Any new work in this county requires buried service.

The only split I am aware of is for 400A, there you have two 200A panels, and they get wired at the time you hook up your service.

I mounted my panel, conduit connection to the new meter pan before they pulled the meter. If I needed, I could throw the 200A CB at the panel that fed the inside panel. It was a no brainer to pull the new circuit wires to the new panel after the new feed was attached. Except some had to be replaced, as they didn't reach the new panel.

Some here say 400A is over kill for a house, but it depends on your load requirements. And your pocket book.

Good luck.

My largest welder is rated some 90A in at 230V but I have been running it for years at lower settings with a smaller breaker (maybe 50A) with no problem. The welder is capable of 400A output but I don't ever use that in my home shop, I bought it because it was a TIG and I wanted to learn to TIG weld aluminum. But, if the need ever came to do some heavy duty welding it would be nice to have the power availability.

Most of my machine tools are 3 phase and I run them mostly from variable frequency inverter drives with single phase in, 3 phase out. This also seems to take care of much of the power factor problems. I ran my 7.5HP lathe just idling the VFD showed 13A to the motor, I put an amp clamp on the supply and it was only drawing 5A. Before buying drives for 3 phase conversion, I used to idle a 10HP motor on single phase and the 3rd leg generated the 3rd phase. This was pretty bad on power factor, I added capacitors to balance and cut the current draw.

RogerN

A sub-panel will always be protected by it's own breaker in the main panel. If you install a 100A sub panel, you will connect it to a 100A breaker to protect the wiring to the sub panel.

When I upgraded the panel in a friend's house, the utility did change the wire. They ran a new heavier gauge triplex all the way from the pole with the transformer to the new mast I installed on the house. The transformer was serving several houses and was adequate, but they would upgrade that too if required. Never seen an issue running large welders and stuff in home shops, it's fairly common. This is in the USA, I can't speak for other countries.

My previous residence was a double wide and I had a 30X50 building where I had my home machine shop, heavy machines including a forklift to move them. Never had any trouble with power running either my home brew 3 phase rotary converter or any of my welders.

RogerN

Welders are not even *that* big of a load. My hot tub pulls almost 50A from a 240V circuit with both pumps, the heater, and the air blower running. Fire up the clothes dryer and that's another nearly 30A, heat pump is another 10-25A depending on conditions. I've had all those running at once on more than one occasion and never had any appreciable sag aside from the momentary surge when the heat pump compressor starts. I'm sure it varies by area, but the supply in my region seems to be quite robust and low impedance.

While on the topic, I have an engineer friend in the UK with whom I've discussed these things at length. In his neighborhood the whole street is on one transformer and the low voltage (240V) runs are longer than anything I've seen over here. He's monitored the line voltage at his home and found that it varies considerably throughout the day, from under 220V to almost 250V. I did the same at my place and never saw it much below 117 or above 121.

Perform a load calculation per NEC Article 220 to see how many amperes you need. Check with the power company to see if you can upgrade.

One solution might be to install new 200 ampere outside service with one 200 ampere main and a 100 ampere submain. Use the 100 ampere submain to feed your existing home service by tapping at the existing panel/main disconnect and use the 200 amperee main to feed a 200 ampere panel in your shop. The proper grounding electrode and bonding jumper would have to be removed from your existing service and installed at your new service. The service entrance conductors would have to be increased in size, probably to 3/0 copper. If you cannot afford an electrician, at least get a qualified inspection of your work before turning on. All new work should conform to the 2008 NEC or current adopted version of the NEC if your local jurisdiction has done that. There are dozens of ways to do this depending on the exisitng configuration. An electrical contractor or experienced electrican could give you some valuable advice after looking at your existing installation.

Is there a special name for a 200A panel that supports 100A breakers? (breaker box, distribution panel, load center...) Most breaker boxes I've seen at the home centers usually only go up to 60A breakers or so.

RogerN