Smoking deal on a backup home generator

[FlyWright]

I was in Costco the other day and came across this Honda Generator deal that is tough to beat. If you need a home generator, this looks like a great deal. Just thought I'd pass it along.

 

[jwnall]

It is a good deal. I agree completely. I especially like that 8500 starting watts.

John

 

[Great Laker]

What is the simplest, least expensive, and a safe way to hook one up to say a refrigerator, furnace and a few lights? I'm familiar with transfer boxes, but they require some substantial rewiring and are not cheap. Running extension cords around can work but is hard for a built in refrigerator and the distances are large covering two floors and a basement.

 

[FlyWright]

I've got to think the transfer box would be the safest and simplest to operate in a power outage. Combining a transfer switch with a remote start capability, your home and the grid are protected from electricity flowing where it shouldn't and make switching over easy.

It may not be the cheapest way, but cheaper is not necessarily safer or simpler.

 

[Great Laker]

Yes, that is the answer I was expecting, but was hoping I would discover something else.

 

[neworleansrich]

Maybe a ggod deal but here on the Disaster Coast, I only recommend going with natural gas. Believe it or not, the Generac units are excellent value and utility. Forget just the frig in a major outage, go for the whole house, AC included.

With a gasoline unit you will run out out of fuel in 3 days unless you own a gas station.

 

[bshillam]

HD has a Yamaha powered generator that is really hard to beat. Look over the specs, including a smart idle. Good for saving fuel when needed. Also has electric start. I bought one. It isn't a true Honda gen but it's about a third of the equal Honda.

RIDGID 6,800-Watt Yamaha 357 cc Electric Start Idle Down Gasoline Powered Portable Generator-RD906812B at The Home Depot

 

[ksanders]

For your portable generator get a small transfer switch, like the ones made by gentran. They make portable generator operation safe and easy.

For long term outages a whole house setup as indicated above is the best bet.

Being in the backup power switchgear business I'm a backup generator psyco.

We run two diesel sets, in a redundant setup. Our time to detect the outage, spin up the generators, and restore power is less than 5 seconds, even if its -50 outside.. We keep 10 days worth of fuel in the day tank and are prepared for an outage lasting several months. A true psyco.

 

[FF]

While the unit shown is a contractor unit (noisy) the hook up is simple.

Simply change the sockets on the unit (or create an adapter) that will alow the noisemaker to plug into the std deck 110 or 220 socket .

Your std power hose is built to be outside , and if you hang the unit from a davit it will produce the least vibration and noise.

In the Carib many leave the noisemaker in a dink, and let it float aft for better Quiet.

Be sure to remove all fuel from the unit if non Ethanol fuel is not used.

The easiest non Ethanol is a 5 Gal can from the local tiny airplane fuel pump. Called an FBO.

 

[CaptTom]

What is the simplest, least expensive, and a safe way to hook one up to say a refrigerator, furnace and a few lights?

Well, it's hard to get simpler and safer than extension cords. The furnace will require some minor re-wiring.

An inexpensive option is a simple DPDT knife switch before the breaker panel. Up for utility, down for genset. Cheap, effective, no chance of backfeeding the grid, and minimal wiring changes. You need to either size your genset to run everything in the house at once, or (my solution) load balance by switching off the breakers you don't need (clothes dryer, air conditioner, etc.) while running off the genset.

Downside is you (or someone who understands what to do) need to be there when the power goes off. Obviously automatic start and automatic load shedding would be better. And a LOT more expensive.

 

[Great Laker]

An inexpensive option is a simple DPDT knife switch before the breaker panel. Up for utility, down for genset. Cheap, effective, no chance of backfeeding the grid, and minimal wiring changes. You need to either size your genset to run everything in the house at once, or (my solution) load balance by switching off the breakers you don't need (clothes dryer, air conditioner, etc.) while running off the genset.

CaptTom. That is an idea worth investigation. It is unlikely we would have an outage more than a few hours more than once every few years, so this looks promising.

Can you show an example DPDT (double pole, double throw) switch that would be appropriate for a 100 amp subpanel? Also, I have two 100 amp panels. Assuming I install two switches, can a single generator be attached to both simultaneously?

 

[CaptTom]

Can you show an example DPDT (double pole, double throw) switch that would be appropriate for a 100 amp subpanel? Also, I have two 100 amp panels. Assuming I install two switches, can a single generator be attached to both simultaneously?

This one seems a little over priced for just a switch, but not too bad.

Inside, it's just a big version of this:

Electrically, I see no reason you couldn't wire the output of the genset to two switches. I'm not sure the practicality though. Two 100A panels suggests a big genset, and now you're getting into the price range where a "proper" auto-start, auto-transfer system is the norm.

 

[ksanders]

CaptTom. That is an idea worth investigation. It is unlikely we would have an outage more than a few hours more than once every few years, so this looks promising.

Can you show an example DPDT (double pole, double throw) switch that would be appropriate for a 100 amp subpanel? Also, I have two 100 amp panels. Assuming I install two switches, can a single generator be attached to both simultaneously?

While the idea of a simple knife switch might sound like a good solution, using a knife switch like the one in the photo should be avoided.

The reason is that the knife switch shown is open, exposing persons to hazardous voltages. You could put it in a can, but then you'd have to open the can to switch sources, and it would not be legal in many jurisdictions.

If you are going to power a 100 amp sub panel then get a simple 100 amp manual transfer switch. They will be in a enclosure, and will have an operating lever on the side.

For a whole house setup things get a little more complicated. You need to have a breaker in between your meter and the transfer switch. This breaker becomes your "service entrance". This breaker can either be separate, or built into a transfer switch. Transfer switches with a service entrance braker installed in them are listed as "service entrance rated"

When buying a transfer switch look for a UL1008 listed unit. UL1008 is the listing, showing that a piece of equipment is certified for use by UL as a transfer switch. Many jurisdictions require a UL1008 listing on transfer switches, as UL listings were incorporated into the 2003 NEC, if my memory is correct.

UL 1008 is not a NEC firm requirement, even though it is listed in the NEC in Annex A. That may sound wishy washy, but heres how it works. Annex A of the NEC is a list of equipment usage, and the UL listing that equipment should have for that usage. Annex A is a guide for inspectors to determine if a piece of equipment is installed and used in the manner that its UL listed for.

The challenge is that inspectors and municipalities have significant lattitude as to what they will accept in their jurisdiction and what they will not accept. Many jurisdictions will not accept a piece of equipment for service unless it carries the proper UL certification for its intended use, as described by Annex A of the NEC.

Case in point is a three way knife switch. If it is not rated with a UL 1008 rating, it can and will be turned down in many jurisdictions. That does not mean its not safe. It just means that the inspector cannot show that its intended use is as a transfer switch.

 

[Great Laker]

CaptTom: "Electrically, I see no reason you couldn't wire the output of the genset to two switches. I'm not sure the practicality though. Two 100A panels suggests a big genset, and now you're getting into the price range where a "proper" auto-start, auto-transfer system is the norm.[/I][/I]"

Thanks for the link. My plan was to use the existing in house breakers to limit the load, and there are some items on each 100A panel I need to power. I realize that makes this approach only practical for me or someone I have trained to operate.

 

[Great Laker]

KSanders: "Case in point is a three way knife switch. If it is not rated with a UL 1008 rating, it can and will be turned down in many jurisdictions. That does not mean its not safe. It just means that the inspector cannot show that its intended use is as a transfer switch."

This helps put the legal aspects into perspective. I wonder how many small town electricians appreciate these requirements.

 

[ksanders]

KSanders: "Case in point is a three way knife switch. If it is not rated with a UL 1008 rating, it can and will be turned down in many jurisdictions. That does not mean its not safe. It just means that the inspector cannot show that its intended use is as a transfer switch."

This helps put the legal aspects into perspective. I wonder how many small town electricians appreciate these requirements.

Out in the country, where you do not need to get a permit and inspection, things are done like they always have been done. The local electrician or the homeowner gets the job done, and for the most part its safe.

The systems that scare me is when a homeowner wires up a generator to a double pole breaker in his panel. That installation is an accident waiting to happen.

 

[FF]

The knife switch violates general safety principals as the noisemaker is a >source< and will need its ground hooked up too.

Simplest safe system has been discussed before , a plug that is the boat loads and two or 3 sockets .

Shore power , noisemaker or inverter would be the sockets , all rated 240V 50A .

Moving the plug is not harder than changing a knife switch and FAR safer.

 

[CaptTom]

While the idea of a simple knife switch might sound like a good solution, using a knife switch like the one in the photo should be avoided.

Oh, yeah, the photo was just a "toy" version of what's inside the box, to show electrically what it does. Obviously the handle is outside the box so you don't have to reach in around live connectors. And I have a service breaker on the utility side, so I'm legal there. Not sure what the switch is certified for, but it's rated for 100A, the same as the service breaker.

 

[ksanders]

The knife switch violates general safety principals as the noisemaker is a >source< and will need its ground hooked up too.

Simplest safe system has been discussed before , a plug that is the boat loads and two or 3 sockets .

Shore power , noisemaker or inverter would be the sockets , all rated 240V 50A .

Moving the plug is not harder than changing a knife switch and FAR safer.

Land based is not the same as boats.

In general, you do not need to switch the neutral in land based systems.

There is the "separately derived source" rule but it only applies if the neutral is ungrounded, which is almost never the case. There are situations where you need to switch the neutral, but they are few and far between for land based systems.

I work with probably a thousand (I do not count them) installations a year, on a nationwide basis and switch the neutral in less than probably 20 of them.

 

[ksanders]

Oh, yeah, the photo was just a "toy" version of what's inside the box, to show electrically what it does. Obviously the handle is outside the box so you don't have to reach in around live connectors. And I have a service breaker on the utility side, so I'm legal there. Not sure what the switch is certified for, but it's rated for 100A, the same as the service breaker.

Then you have a manual transfer switch. If its in and working, fantastic. You are one of the folks that understands that a transfer switch is a necessary safety device for generator installations.

My comments were based on the photo you provided.

 

[FF]

<There is the "separately derived source" rule but it only applies if the neutral is ungrounded, which is almost never the case. There are situations where you need to switch the neutral, but they are few and far between for land based systems.

I work with probably a thousand (I do not count them) installations a year, on a nationwide basis and switch the neutral in less than probably 20 of them.>

I guess the 20 are boats.

The neutral is grounded at the source , for the dockside powerhose its somewhere in the boat yard electric system.

For a noisemaker IT is the source , so the neutral will be grounded there.

Same for an inverter , IT is the source so is internally grounded.

The neutral and ground for a dirt house line are kept apart .

IF the neutral and ground are combined at either the noisemaker or inverter this must be accounted for in the transfer mechanism.

A complex transfer box or a $6.00 plug.

 

[ksanders]

<There is the "separately derived source" rule but it only applies if the neutral is ungrounded, which is almost never the case. There are situations where you need to switch the neutral, but they are few and far between for land based systems.

I work with probably a thousand (I do not count them) installations a year, on a nationwide basis and switch the neutral in less than probably 20 of them.>

I guess the 20 are boats.

The neutral is grounded at the source , for the dockside powerhose its somewhere in the boat yard electric system.

For a noisemaker IT is the source , so the neutral will be grounded there.

Same for an inverter , IT is the source so is internally grounded.

The neutral and ground for a dirt house line are kept apart .

IF the neutral and ground are combined at either the noisemaker or inverter this must be accounted for in the transfer mechanism.

A complex transfer box or a $6.00 plug.

FF, we are discussing land based systems here. Lets keep tyhe discussion to land based systems to avoid confusing people.

Here's a quotation from the NEC Article 250.20D

"An alternate alternating current power source
such as an on-site generator is not a separately
derived system if the neutral is solidly interconnected
to a service-supplied system neutral.”​

This is the basis of why on a land based system we do not have to switch the neutral for most backup generator installations.

 

[FF]

Here's a quotation from the NEC Article 250.20D

"An alternate alternating current power source
such as an on-site generator is not a separately
derived system if the neutral is solidly interconnected
to a service-supplied system neutral.”

Quite correct as most dirt houses tie the neutral to a water pipe ground .

Not a good idea on a boat.
​

 

[ksanders]

Here's a quotation from the NEC Article 250.20D

"An alternate alternating current power source
such as an on-site generator is not a separately
derived system if the neutral is solidly interconnected
to a service-supplied system neutral.”​

Quite correct as most dirt houses tie the neutral to a water pipe ground .​

Not a good idea on a boat.​

FF, the proper way to ground the neutral on a residence is to use ground rods, two of them is better.

Something people do not realize is that the power company grounds the neutral at every pole. Thats the little ground wire stapled to the side of every pole, it grounds the neutral.

On the secondary side of the power transformer, the neutral is also grounded.

In the power world, if its not energized, its grounded.