Water heater wiring for generator hookup and to 120 VAC power?

[stu]

A water heater is in the garage about 6 feet from a window.

There is a 3 wire cable to the water heater +120 -120 and a bare wire grounded to the frame. No separate white neutral.

A generator sits at window level with ther exhasust extended though a 'dryer vent' type arrangement and is available for emergency power within a few minutes.

The generator frame is grounded to the outside ground in the earth.

I was thinking of using a 20 foot 3 wire cable to the dryer receptacle like we did during Hurricane Jeanne but I considered the following:

MAIN DISCONNECT IS OFF!! it is off, it is OFF!!!! (no way is it ON!)

One hot wire going from the panel to the water heater goes to the center terminal of SPDT switch. The other panel wire goes to the water heater and to one generator wire.

Water heater on one end of the SPDT and generator on the other.

1> Using the SPDT we break the wire to the heating elements and switch it to the generator.

2> I use the generator to back feed the panel 240 VAC.

3> If I wish to heat water at 120VAC I connect the open water heater wire to ground.

Like this:

Generator ---------------------------------: (generator lead A permanently connected to water heater wire #1)

Panel -120 ----------------:-water heater wire #1 connected

Panel +120--------- --\\ ------------ water heater wire #2 open Control Switch SPDT \\-------- (generator lead B connected)

Panel ground_______________Generator Ground and generator Neutral

Switch in GENERATOR Mode feeding Panel 240 VAC When switch is thrown, generator B is open and watewr heater wire #2 is connected to panel (normal power on position)

Should I wish 120 VAC heating with GENERATOR, short water heater wire #2 to ground wire (no neutral available in cable).

Just 2 single pole switches and we would be on backup generator with a choice of slow (1/4 power) hot water.

NOTE* The Generator cable has a 4 conductor male plug and it is not plugged in until the Main Breaker is OFF!

The cable will be plugged into a dummy receptacle until just before using because one lead is 'hot'.

Any negative consequences to the above wiring idea?

[Spud]

snip

Under no circumstances should portable generators be used indoors, including inside a garage, carport, basement, crawlspace, or other enclosed or partially-enclosed area, even with ventilation. Opening doors and windows or using fans will not prevent CO buildup in the home. The CO from generators can rapidly lead to full incapacitation and death, but CO can't be seen or smelled. Even if you cannot smell exhaust fumes, you may still be exposed to CO. If you start to feel sick, dizzy, or weak while using a generator, get to fresh air RIGHT AWAY - DO NOT DELAY.

Because you may have windows open to get fresh air while the power is out, be sure to place the generator away from windows, doors, and vents that could allow CO to come indoors

[stu]

Spud,

With all due respect, I welded an exhaust extendion and placed it through an airtight seal to the window.

Like a window A/C installation there is no, I repeat, NO exhaust fumes inside the garage. Have you ever been inside a commercial repair facility that pipes the auto exhausts to the vehicles they are working on?

That is a loose connection and a little exhaust can comwe back into the garage. Not in my situation.

BTW My last condo had a humongeous diesel generator for emergency power located inside our 21 story building. Our unit was next to it. It was exhausted to the outside. You have to know what you are doing to be safe.

Generically, you are correct. BUT! Under the conditions that I described, not a problem.

I also use a CO2 detector.

[wkearney99]

Homemade welds and seals, sure, that's safe....

Which often have a good bit of OTHER air circulation equipment. Unlike a residential garage that typically has NONE.

A professionally installed and inspected setup is one thing, your's isn't. You can't compare them.

Sez who?

Which will do no good whatsoever. You need to be monitoring for carbon MONOXIDE (CO), not simply carbon DIOXIDE (co2). Likewise they need to be mounted properly and in locations best suited for safety. One in the bedroom is a LOT more valuable in than one mounted too low in the garage.

[PanHandler]

There are ways to protect fools from themselves, but there's no help for DAMN fools.

[Toller]

I've been tempted to do that. I just leave it in my garage with a front and rear door open a foot. Yes, I know how dangerous it is, but it doesn't seem to bother the CO detector.

Is your generator ground connected to the frame? If so, you don't want to ground the frame again. And if it isn't there is no particular reason to gound the frame.

Well, it appears (as well as I could understand it) to be okay, aside from being illegal and dangerous, but why do something so complicated? What are you trying to accomplish?

[Ignoramus5455]

Stu, beware that there are many issues involved with piping exhaust through welded pipes. Vibration and high temperature and potentially corrosive exhaust gases, for example.

The consequence of failure of your exhaust system can be lethal and quick. A CO (not CO2 as you said) warning system is a good thing, but is not bulletproof and batteries often die.

Exhaust pipes can be welded and generators are often installed indoors, but beware of unexpected issues, if you are not a professional installer of generators.

i

[w_tom]

The same switch that connects generator to water heater must also disconnect AC mains from water heater. Switch must be 'break before make' type. It does not matter how many times you say "it is off". Humans have a bad tendency to always make the exception occur. A design must be human proof.

Design must be 'not mechanically possible' to ever connect generator until heater has been disconnected from AC mains. Switching equipment is simple to obtain which is just another reason why the heater must always disconnect from AC mains before generator makes a connection. Any residential procedure that calls for human knowledge is unnecessarily and unacceptfully dangerous.

If anyone ever makes a mistake (connects AC mains and generator together), then 100% blame belongs on the human who built that mistake. If anyone can make a mistake, that human who installed the dangerous system should be hung by his balls

- this last sentence > A water heater is in the garage about 6 feet from a window.

[stu]

Toller,

Thanks for your thoughtful reply.

I meant CO detector, but couldn't be give thethe benfit of the doubt.

If you lived therough Francism Jeanne, and wilma, you would understand what we are attempting to accomplish in SE FL.

I want the quickest, , quietest, cheapest, longest running, genrator hookup for standy for minimum power and which requires minimum effort to get running.

First the generator garage issue: My welds are strong enough to trust my life on when I ride my recumbent trikes and other vehicles that I have built over the years. Also, my $100 elevator in daily use for over 3 years was also condemned by the usual Google lurkers who never seem to trust their own abilities to build anything that their life would depend upon. What happened to the pioneer spirit? "Leave it to the professionals" is their motto. True in many cases but not in all cases. Why have a Forum on Home repair? Just use the Yellow pages and hire a pro.

There are 2 closed interior doors separating the garage from the house. The Garage door will be partially open for ventillation and for oxygen for the generator.

The genertator is a 3000-3500 watt 6.5 hp model. Modest output, enough for a refridge and a few lights etc.

Complication is not the case. Just the opposite. A short 3 wire cable from the generator to a junction box and 2 switches.

Throw one switch for generator power to the entire house.

Throw the other switch for 120 VAC hot water.

What could be simpler with fewer wires or switches?

The 4th crooked lead in the generator receptacle does not measure 'short' to the generator case not to any other terminal.

[w_tom]

Ignoramus5455 is citing basic engineering conceps. Not if. When failure happens, will the system still not let CO enter the building? Why not just put exhaust pipes inside a vehicle? Because when pipes crack, there is another protection system to keep vehicle occupants from CO poisoning. Systems designed for human safety must always be redundant.

That also applies to how the generator c> Stu, beware that there are many issues involved with piping exhaust

[w_tom]

[stu]

Safety Ground at the panel box wired to Neutral.

[Steve Kraus]

I'd feel better about it if you have a flexible section near the generator. If your construction is entirely rigid then forget it, it will eventually break no matter how good your welds are unless it's *extremely* short. Is it a threaded connection into the engine? That's a good place for a break if the vibrating engine is rigidly connected to a lengthy pipe. That condo emergency genset you mention...if it was indoors it surely had some sort of flexible pipe connection. Does your engine vent the crankcase back to the intake? Finally, a decent ventilation fan either bringing in fresh air or exhausting inside air, with either a vent or window that will be open during generator runs to allow for circulation is a bare minimum. Then maybe.

Is this gasoline or NG? Where is the tank vented? What about spills on refueling? So much simpler and safer just to take the thing outside. Then you can tell everyone about how you will hook it up via the A/C disconnect box.

[Ignoramus5455]

Yes. In any projects, it is important to understand the cost of failure.

If (or when) his homemade weld cracks due to heat distortion of metal, residual stresses from welding, corrosive gases, condensation, and vibration (all issues that can be addressed but require careful engineering approach) he would have a system that quickly pumps carbon monoxide and hot exhaust gas into his garage.

He is hoping that he would be able to hear the CO detector when the diesel is running in his garage, wake up from the CO detector, understand what is going on (all the while a diesel is pumping CO into his house), get out of bedroom, get into the garage (all smokey and very hot and full of poisonous CO), turn off the genset, get out of the garage, save his family who need saving, without succumbing to CO.

Maybe he would get lucky and his welds would not crack. (esp. if he does not use his genset much).

Maybe he would get lucky and if the welds break, they would develop a small leak, which a CO detector would notice.

Maybe he would be lucky enough to actually hear the CO detector when his (possibly loud) generator is running. Etc etc.

He is more likely to be lucky and die from something else eventually, like old age. But, the odds and the consequences do not make it worthwhile to install it inside by himself. It is cheaper to just buy an approved exhaust system, if it exists.

Also, the issues of the generator dumping about 1/3 of energy (approximately the same kW as electricity produced) into the garage as heat loss, needs to be explored. For a 10 kW generator, he'd have about 10 kW heater in the garage.

i

[Ignoramus5455]

Forgot to say, I also considered installing my genset in my garage, and decided against it for the reasons that you and I mentioned.

Now it is installed outside:

>> Ignoramus5455 is citing basic engineering conceps. Not if.

[mm]

I don't see how that would make a difference. The engine sucks in air and blows iit out the rear, and out the garage door through the hose. How is any other air circuilation equipment necessary?

....

Of course that is what he meant. People mistype on the net about 10 or 20 times as often as they do in their other correspondence.

Remove NOPSAM to email me. Please let me know if you have posted also.

[Ignoramus5455]

Because the generator produces other heat besides that which is exhausted through the exhaust.

The equation roughly is

Generator power in kW = Exhaust heat carried = Cooling air warmed.

In other words, 33% of energy consumed (burned fuel) is electricity,

33% is exhaust heat, and 33% is cooling heat. It needs to be removed from the garage. Percentages are approximate. i

[stu]

Big system. How many KW? Can you talk over it? How much did the entire project cost.

My generator is 67 db and it cost $269.95 at Pep Boys is at the other end of the bell curve..

I can talk over it when it is running. It sits on tubber shock mounts and hardly vibrates.

I consider it disposeable and intend to use it less than 100 hours per year.

Your gen can suck my gen in and spit it out the other end.

[Edwin Pawlowski]

The internet is amazing. You are able to judge from a newsgroup posting the the installaion is no good. You are able to discern his design, his welding ability, his safety precuations. I am in awe!

[Ignoramus5455]

It is rated for 7 kW, and can produce that continuously 24x7. It can produce a little more than that, I tried it at 7.5 kW, it produced that much as well.

For these little ones, actually piping exhaust out may not be easy.

Plus, does it pay off to work so hard to make an exhaust piping system for something that may not be likely to live long.

That's very, very nice. Mine produces 75 dB after I built an enclosure around it.

Then perhaps making an elaborate system for it is not warranted?

I really, really like this genset, it is one of my favorite things.

i