200 Amp Service, Tankless water heater

You almost certainly already had 100 amp to the stack/meter. It's been over 40 years since anything else has been run. 200 amps requires replacement of the service feed cable from the transformer, and MAY require replacing the transformer, depending where you are and how heavily loaded it already is.

Reply to
clare
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To meet code, the 200 amp main breaker has to be pulled and replaced with a 100 amp breaker, or a 100 amp breaker needs to be installed "upstream" - like at the pole.

Reply to
clare

They MIGHT have a 100 amp "pole fuse" installed that protects their cable. If he draws over 100 amps he will lose power and will have to call the power co in to replace the fuse and the overhead cable.

Reply to
clare

You'll need a big ass generator when your power goes out. Personally I'd stick with a tank type water heater.

Reply to
N. Cognito

With an overhead service, you are usually only responsible for the SE cable/conductors going up the side of the house and through the wall. Some utilities will even give you the meter can. The wild card is what you have to do to your existing panel. You can put in a grounding bus, lift the bonding jumper, swing over the grounds and run in a 4 wire feeder from a 200a meter/main and then run your new loads from that main. This seems to be a pretty popular option. The big labor hog is swapping out the existing panel because you may end up with wires that are too short, perhaps space problems where it is mounted and then that unknown that always pops up. That might also trigger the requirement for AFCIs in some jurisdictions and that can really pop the top on that can of worms.

Reply to
gfretwell

I can't speak for all of the utilities but FPL runs the exact same triplex for 100a as they do for 200a and it is ~2ga aluminum. When I heavied my service up from 100 to 200 they said the overhead was fine but I had to run a 4/0 down to the meter and through the wall.

Reply to
gfretwell

The power company does not give a rats ass about their cable. The only overcurrent protection is on the primary to the transformer and for the user, that means the available fault current is 22ka or more in most cases. For all extents and purposes, service conductors have ZERO over current protection. That is why the rules are so much tougher about how they are run.

Reply to
gfretwell

Most residential users do not have a generator big enough to run the water heater if they want to run anything else.

Reply to
gfretwell

While most will not run much but the water heater, you can get the water heater hot and cut it off, then fill the tub or take a quick shower. Then heat the water again.

Reply to
Ralph Mowery

That's because they now assume 200 amp to be "normal". In a 40 year old subdivision, 100 amp was "normal" and updating to 200 amp requires total cable replacement.

Reply to
clare

This house was built in 1963 and they has 100 in it when I bought it in 84. The #2 triplex is pretty much what they install for everything up to 200a.

Reply to
gfretwell

Reply to
DanG

It seems that would depend on the delta T required and the amps available. It's not rocket science. If you want a given flow of water raised a given temp, you just need enough power. They can provide the temp rise, you just need to provide the power.

Reply to
trader_4

Sometimes it is just not practical to provide enough power to do that. Just as I stated above, at work it would have required running lots of conduit and wire for the tankless heater.

I am not sure if the tankless water heater could have a longer path inside it to absorbe more heat as the water passes through or not and reduce the ammount of power needed.

Reply to
Ralph Mowery

No disagreement there. The other poster claimed that he was not aware of any that could provide the delta T. The alleged non-existence of capable units and if it's practical, cost justified, are very different things.

Reply to
trader_4

tankless manufacturers recommend 2 tankless in series, that doubles the cost, and doubles the power needs......

Reply to
bob haller

snipped-for-privacy@aol.com posted for all of us...

+1

Same for PECO.

Reply to
Tekkie®

First off, WHY do you want a tankless water heater? I'm not being a smart ass, I really dont know anything about them, and dont understand what the advantage is over a traditional tank water heater....

Secondly, I'm wondering if yiu're being taken for something you dont need. (Meaning the 200A upgrade). How many watts does that thing draw? If you already have an electric "tank type" water heater, they have two elements which normally use 4500 Watt elements. If this tankless uses about the same wattage, then there is no reason to need the 200A upgrade.

If you ask me, those tankless heaters dont save anything except a few feet of space in your basement or whereever the water heater is installed. Like I said, I am not familiar with them, except I know a local business that has one, and Ive seen it. It sits in a closet between the Mens and Womens restrooms, and all it does is provide hot water for the sinks in those two restrooms. Yea, it does save some apce in that closet, but I know the owner said it was very costly. But I also know the building was damaged by a flood in the basement which ruined the old tank water heater, so he moved it upstairs in that closet. He could have installed a tank type in there, but the damages were covered by insurance, so I guess he just let the rebuilders do waht they wanted.

It seems to work fine, but aside from saving a little space, I dont see any other advantage to it!!!

Reply to
Jerry.Tan

The main advantages are an unlimited supply of hot water and no standby losses that you'd have from a tank. The standby losses however don't appear to be all that great. My gas bill in summer is just $17 a month and that includes not only the standby usage, but the hot water used too.

A tankless that replaces a tank type has to use many times the wattage, because it has no tank. What the tank heater does in hours, the tankless has to do instantly. If it's a whole house tankless, or even one for a whole bathroom, needing a service upgrade isn't unusual. It's also not unusual to need piping and/or service upgrade to support a gas one either.

Reply to
trader_4

Fair questions. They offer energy savings as you don't keep hot a 60 or 80 gallon tank of hot water all the time. You just make what you need when you need it.

You offer a lot of advice considering you admit you know nothing about them. Depending on size, the electrics run from 15 to 30 KW. That means it can pull 125 amps of the 200 available on a decent sized unit.

Reply to
Ed Pawlowski

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