Electricians - generator to house

[olds]

I was told today that if you turn off the main service breaker to your house and plug your generator into the dryer outlet (220v) that it will feed the 110 bus bars giving you your 110v circuits.
This would obviously be up to the wattage the generator is rated for/would provide.

Anyone confirm this? I doubt it's legal as you could back feed the power line if you don't turn off the breaker (shocking any repair person) or destroy your generator/home wiring if the power came on with the generator running and the breaker closed.

 

[BigJ]

Yes it'll work.

No it is not a good idea. Pony up the cash for a manual transfer switch.

 

[marvdmartian]

I don't know the legality of it, but when I live in Guam, back in the 90's, that was a common way for people to hook their generators up to their house circuits, instead of running a bunch of inefficient (and expensive) extension cords. Just make certain that you go from the 220vAC outlet on your generator, to the dryer plug (also 220vAC), and don't screw up the order of your connections, or you'll possibly energize your ground, etc.

Also, realize that things like a/c units, and pretty much anything with a major heating coil, are probably not going to run off a generator (unless it's a BIG honkin' one, and then why would you use this cheesy method! ). I have seen a 4000watt model run a refrigerator and some small fans and lights......which is usually what you want anyways.

 

[Specop 007]

Theres a whole lot of "what ifs" invovled with generatgors and power. Throwing your main may or may not actually stop power from backfeeding into the system. If it doesnt stop the backfeed, you stand a very real chance of killing a lineman.
Additionally, sometimes breakers wont pop if power is fed the wrong way through them.

To put it simply, dont fuck around with generators. Doing it wrong could kill a lineman, kill you or start a fire in your house. TYransfer switchs arent all that much, it wouldnt hurt to get it done right.

 

[BigJ]

Originally posted by: Specop 007
Theres a whole lot of "what ifs" invovled with generatgors and power. Throwing your main may or may not actually stop power from backfeeding into the system. If it doesnt stop the backfeed, you stand a very real chance of killing a lineman.
Additionally, sometimes breakers wont pop if power is fed the wrong way through them.

To put it simply, dont fuck around with generators. Doing it wrong could kill a lineman, kill you or start a fire in your house. TYransfer switchs arent all that much, it wouldnt hurt to get it done right.

Unfortunately, people don't give a flying fuck when it comes to electricity. Which is interesting, considering it stands a very good chance of killing someone if you don't do it right.

 

[bctbct]

I raised this issue a month or so ago. Yes you have the concept correct. Check your local laws, it is perfectly legal for me and I have yet to find anywhere it is illegal except possible CA.

If the main turns off power leading to your house, I dont see how you could backfeed power from your house.

 

[Specop 007]

Do me a favor man, read this as well as the other post it links to.

 

[Specop 007]

Originally posted by: bctbct
I raised this issue a month or so ago. Yes you have the concept correct. Check your local laws, it is perfectly legal for me and I have yet to find anywhere it is illegal except possible CA.

If the main turns off power leading to your house, I dont see how you could backfeed power from your house.

Because theres more then 1 way a switch can "turn off the power". Personally, I would say screw the local laws and check with my local electric company. I want them to tell me "Yes, doing this will work".

 

[BigJ]

Originally posted by: bctbct
I raised this issue a month or so ago. Yes you have the concept correct. Check your local laws, it is perfectly legal for me and I have yet to find anywhere it is illegal except possible CA.

If the main turns off power leading to your house, I dont see how you could backfeed power from your house.

They added the exception in the 2005 NEC. Here is the exact wording:

Exception: Temporary connection of a portable generator without transfer equipment
shall be permitted where conditions of maintenance and supervision ensure that only
qualified persons service the installation and where the normal supply is physically
isolated by a lockable disconnect means or by disconnection of the normal supply
conductors.

In other words, you better have your shit in order if you do it. It's not really meant for Joe Blow to hook up his genny without a transfer switch.

 

[bctbct]

Originally posted by: BigJ

They added the exception in the 2005 NEC. Here is the exact wording:

Exception: Temporary connection of a portable generator without transfer equipment
shall be permitted where conditions of maintenance and supervision ensure that only
qualified persons service the installation and where the normal supply is physically
isolated by a lockable disconnect means or by disconnection of the normal supply
conductors.

In other words, you better have your shit in order if you do it. It's not really meant for Joe Blow to hook up his genny without a transfer switch.

Dont you love how they can't ever seem to put anything in plain english that everyone interprets the same way.

Qualified persons is debatable, I would interpret the bolded areas to be the main breaker.

 

[Evadman]

There is nothing that would physically make that arrangement fail.

To bigJ & Specop 007's points, if you do not flip the main breaker, you will actually back feed the grid. Theoretically, your neighbors would all see power, and you would also energize the high voltage lines. Someone up on a pole could be killed since they expect the power to be off, and the line dead.

Originally posted by: Specop 007
Additionally, sometimes breakers wont pop if power is fed the wrong way through them.

Only if the breaker is defective, in which case it wouldn't matter which way the power is 'flowing'. The breaker to the stove/dryer will still flip if you try putting > amperage than the breaker is rated for. It doesn't matter which way the amperage is 'flowing' since it reverses 120 times (60 hertz) a second.

Originally posted by: bctbct
I would interpret the bolded areas to be the main breaker.

Tripping the breaker does not disconnect the neutral. Theoretically it should not matter since neutral is supposed to be tied to ground, so there will not be a voltage on the neutral feed back to the pole. But if something is wrong in your box there will be issues.

 

[BigJ]

Originally posted by: bctbct

Originally posted by: BigJ

They added the exception in the 2005 NEC. Here is the exact wording:

Exception: Temporary connection of a portable generator without transfer equipment
shall be permitted where conditions of maintenance and supervision ensure that only
qualified persons service the installation and where the normal supply is physically
isolated by a lockable disconnect means or by disconnection of the normal supply
conductors.

In other words, you better have your shit in order if you do it. It's not really meant for Joe Blow to hook up his genny without a transfer switch.

Dont you love how they can't ever seem to put anything in plain english that everyone interprets the same way.

Qualified persons is debatable, I would interpret the bolded areas to be the main breaker.

This is what the NFPA has to say on it:

This exception was added in the 2005 Code. This exception provides requirements for
the connection of loads to a generator without the use of a transfer switch, where the
installation is under the supervision of qualified service personnel. Such applications
often occur when necessary for equipment maintenance or breakdown or when there is
an extended power outage. In such instances, a portable generator can be brought to a
facility and connected to the existing distribution system. The supervision by qualified
personnel is critical to ensuring that a dangerous backfeed condition is not created by
connecting the generator to the system without the benefit of transfer equipment.

As you can see, this is not meant for the average home user.

Number one way to see if it's legal in your area:

Call the AHJ.

 

[Specop 007]

Originally posted by: Evadman

Originally posted by: Specop 007
Additionally, sometimes breakers wont pop if power is fed the wrong way through them.

Only if the breaker is defective, in which case it wouldn't matter which way the power is 'flowing'. The breaker to the stove/dryer will still flip if you try putting > amperage than the breaker is rated for. It doesn't matter which way the amperage is 'flowing' since it reverses 120 times (60 hertz) a second.

That was what I originally thought as well, but I had heard differing opinions from people so wasnt 100% positive.
And I've never felt the need to fire up the genny and intentionally overload it to find out.

 

[bctbct]

Originally posted by: BigJ

Originally posted by: bctbct

Originally posted by: BigJ

They added the exception in the 2005 NEC. Here is the exact wording:

Exception: Temporary connection of a portable generator without transfer equipment
shall be permitted where conditions of maintenance and supervision ensure that only
qualified persons service the installation and where the normal supply is physically
isolated by a lockable disconnect means or by disconnection of the normal supply
conductors.

In other words, you better have your shit in order if you do it. It's not really meant for Joe Blow to hook up his genny without a transfer switch.

Dont you love how they can't ever seem to put anything in plain english that everyone interprets the same way.

Qualified persons is debatable, I would interpret the bolded areas to be the main breaker.

This is what the NFPA has to say on it:

This exception was added in the 2005 Code. This exception provides requirements for
the connection of loads to a generator without the use of a transfer switch, where the
installation is under the supervision of qualified service personnel. Such applications
often occur when necessary for equipment maintenance or breakdown or when there is
an extended power outage. In such instances, a portable generator can be brought to a
facility and connected to the existing distribution system. The supervision by qualified
personnel is critical to ensuring that a dangerous backfeed condition is not created by
connecting the generator to the system without the benefit of transfer equipment.

As you can see, this is not meant for the average home user.

I think your reference is to whether or not a commercial facility can be connected, I dont think its specific to residential applications. I also note they do not come out and say that a licensed electrician is required.

Dont get me wrong I am only advocating this move if you are in emergency need of power. Some homes here went more than 10 days without power with subfreezing temps. If you have kids, pets and grandma to keep alive, turn off the main and connect the generator to run some heat.

 

[BigJ]

Originally posted by: bctbct

I think your reference is to whether or not a commercial facility can be connected, I dont think its specific to residential applications. I also note they do not come out and say that a licensed electrician is required.

Dont get me wrong I am only advocating this move if you are in emergency need of power. Some homes here went more than 10 days without power with subfreezing temps. If you have kids, pets and grandma to keep alive, turn off the main and connect the generator to run some heat.

No, 702 and 702.6 of the NEC do not only pertain to commercial wiring.

702.1 Scope
The provisions of this article apply to the installation and operation of optional standby
systems.
The systems covered by this article consist of those that are permanently installed in their
entirety, including prime movers, and those that are arranged for a connection to a
premises wiring system from a portable alternate power supply.
702.2 Definition
Optional Standby Systems. Those systems intended to supply power to public or private
facilities or property where life safety does not depend on the performance of the system.
Optional standby systems are intended to supply on-site generated power to selected
loads either automatically or manually.

Again, call up your housing authority and see if it's legal to connect a generator without a transfer switch at your home. You may have a specific exemption in your area that allows it. Generally, you are not allowed to hook up the genny without a transfer switch.

 

[bctbct]

Originally posted by: BigJ

Originally posted by: bctbct

I think your reference is to whether or not a commercial facility can be connected, I dont think its specific to residential applications. I also note they do not come out and say that a licensed electrician is required.

Dont get me wrong I am only advocating this move if you are in emergency need of power. Some homes here went more than 10 days without power with subfreezing temps. If you have kids, pets and grandma to keep alive, turn off the main and connect the generator to run some heat.

No, 702 and 702.6 of the NEC do not only pertain to commercial wiring.

702.1 Scope
The provisions of this article apply to the installation and operation of optional standby
systems.
The systems covered by this article consist of those that are permanently installed in their
entirety, including prime movers, and those that are arranged for a connection to a
premises wiring system from a portable alternate power supply.
702.2 Definition
Optional Standby Systems. Those systems intended to supply power to public or private
facilities or property where life safety does not depend on the performance of the system.
Optional standby systems are intended to supply on-site generated power to selected
loads either automatically or manually.

Again, call up your housing authority and see if it's legal to connect a generator without a transfer switch at your home. You may have a specific exemption in your area that allows it. Generally, you are not allowed to hook up the genny without a transfer switch.

I already know that its not illegal. The day after the storm the power co. ran commercials cautioning people to throw the main and that workers in the areas would ask generators be turned off if they came across them as they connected lines.

 

[BigJ]

Originally posted by: bctbct

Originally posted by: BigJ

Originally posted by: bctbct

I think your reference is to whether or not a commercial facility can be connected, I dont think its specific to residential applications. I also note they do not come out and say that a licensed electrician is required.

Dont get me wrong I am only advocating this move if you are in emergency need of power. Some homes here went more than 10 days without power with subfreezing temps. If you have kids, pets and grandma to keep alive, turn off the main and connect the generator to run some heat.

No, 702 and 702.6 of the NEC do not only pertain to commercial wiring.

702.1 Scope
The provisions of this article apply to the installation and operation of optional standby
systems.
The systems covered by this article consist of those that are permanently installed in their
entirety, including prime movers, and those that are arranged for a connection to a
premises wiring system from a portable alternate power supply.
702.2 Definition
Optional Standby Systems. Those systems intended to supply power to public or private
facilities or property where life safety does not depend on the performance of the system.
Optional standby systems are intended to supply on-site generated power to selected
loads either automatically or manually.

Again, call up your housing authority and see if it's legal to connect a generator without a transfer switch at your home. You may have a specific exemption in your area that allows it. Generally, you are not allowed to hook up the genny without a transfer switch.

I already know that its not illegal. The day after the storm the power co. ran commercials cautioning people to throw the main and that workers in the areas would ask generators be turned off if they came across them as they connected lines.

Honestly, that means nothing. All that says to me is the electric company is looking out for their employees.

So you've actually talked to the office that regulates building codes in your area and it's allowed? Then good for you.

EDIT: PS. Transfer switch is incorrect, transfer means is correct. Something like an interlock kit would also work.

 

[bctbct]

Originally posted by: BigJ

Originally posted by: bctbct

Originally posted by: BigJ

Originally posted by: bctbct

I think your reference is to whether or not a commercial facility can be connected, I dont think its specific to residential applications. I also note they do not come out and say that a licensed electrician is required.

Dont get me wrong I am only advocating this move if you are in emergency need of power. Some homes here went more than 10 days without power with subfreezing temps. If you have kids, pets and grandma to keep alive, turn off the main and connect the generator to run some heat.

No, 702 and 702.6 of the NEC do not only pertain to commercial wiring.

702.1 Scope
The provisions of this article apply to the installation and operation of optional standby
systems.
The systems covered by this article consist of those that are permanently installed in their
entirety, including prime movers, and those that are arranged for a connection to a
premises wiring system from a portable alternate power supply.
702.2 Definition
Optional Standby Systems. Those systems intended to supply power to public or private
facilities or property where life safety does not depend on the performance of the system.
Optional standby systems are intended to supply on-site generated power to selected
loads either automatically or manually.

Again, call up your housing authority and see if it's legal to connect a generator without a transfer switch at your home. You may have a specific exemption in your area that allows it. Generally, you are not allowed to hook up the genny without a transfer switch.

I already know that its not illegal. The day after the storm the power co. ran commercials cautioning people to throw the main and that workers in the areas would ask generators be turned off if they came across them as they connected lines.

Honestly, that means nothing. All that says to me is the electric company is looking out for their employees.

So you've actually talked to the office that regulates building codes in your area and it's allowed? Then good for you.

I am beginning to think you just want to argue. I have had at least 10 conversations with local licensed electricians about this subject. None of them ever told me it was a) illegal b) dangerous.

If you want to win this arguement you do the leg work. Post info that it is illegal. The NEC doesnt say it illegal or to check with your local laws. The only reference I saw in my search was a power company in CA.

 

[BigJ]

Originally posted by: bctbct

I am beginning to think you just want to argue. I have had at least 10 conversations with local licensed electricians about this subject. None of them ever told me it was a) illegal b) dangerous.

If you want to win this arguement you do the leg work. Post info that it is illegal. The NEC doesnt say it illegal or to check with your local laws. The only reference I saw in my search was a power company in CA.

Like I said before, you may have an exemption. The NEC is a national guideline. Local codes will often have rules specifically prohibiting or allowing items stated in the NEC. Why do you think you have to be licensed by your state and not nationally?

Good for you and your local electrican talks. I can do one better than having random local electricians. There's 4 of them in my best friend's family, along with another friend of mine being one. All licensed, unionized, and working in NYC.

Transfer switch was incorrect. Transfer means is more correct. For example, google "interlock kit." It prevents you from having your main breaker thrown on and also having the circuit feeding from the generator on at the same time. It is not a transfer switch, but a transfer mechanism.

And apparently, you don't google very well. From the Electric Cooperatives of Arkanas, one of the first links:
http://www.aecc.com/be-prepared/standby-generator/

Adding a standby generator to the electrical system of a home, farm or business requires a suitable transfer switch to disconnect the electric loads from the power supplier's utility grid. This is a requirement of the National Electrical Code (see NEC Article 702-6) and all electric power suppliers, for two very good reasons: (1) it prevents the back flow of current into the utility's lines during an outage, which could electrocute linemen working to restore power; and (2) it prevents damage to the generator when regular electric service has been restored, which can destroy the generator.

Google generator transfer switch 702.6

You'll get a bunch of results showing that a transfer means is required.

Like I said before, the whole point of the code is to make sure that you cannot be hooked up to your genny and main line at the same time. A transfer switch or interlock kit accomplish this. Simply throwing your breaker does not, because it is easily switched back on. You would have to physically remove the interlock kit or bypass the transfer switch.

 

[olds]

Originally posted by: Specop 007
Theres a whole lot of "what ifs" invovled with generatgors and power. Throwing your main may or may not actually stop power from backfeeding into the system. If it doesnt stop the backfeed, you stand a very real chance of killing a lineman.
Additionally, sometimes breakers wont pop if power is fed the wrong way through them.

To put it simply, dont fuck around with generators. Doing it wrong could kill a lineman, kill you or start a fire in your house. TYransfer switchs arent all that much, it wouldnt hurt to get it done right.

How is the switch installed?
I don't use the dryer circuit at all, could this be used if needed?

EDIT
Looks like it installs at the service panel?

http://www.northerntool.com/we...70_200196674_200196674

 

[AlienCraft]

Originally posted by: bctbct
I raised this issue a month or so ago. Yes you have the concept correct. Check your local laws, it is perfectly legal for me and I have yet to find anywhere it is illegal except possible CA.

If the main turns off power leading to your house, I dont see how you could backfeed power from your house.

Unless you're in Mexico,us folks in the United States, electrical codes are goverend by the NATIONAL Electrical Code, and I will gurantee you that connecting a generator in the manner described via a 220volt outlet being fed in reverse is not acceptable anywhere.
Furthermore, I challenge you to prove otherwise.
If there is a plug with a hot & neutral reversed, that neutral line is now feeding back into the system, the voltage present at the generator, THAT is how a backfeed gets around a standard main breaker thrown OFF.

 

[BigJ]

Originally posted by: oldsmoboat

Originally posted by: Specop 007
Theres a whole lot of "what ifs" invovled with generatgors and power. Throwing your main may or may not actually stop power from backfeeding into the system. If it doesnt stop the backfeed, you stand a very real chance of killing a lineman.
Additionally, sometimes breakers wont pop if power is fed the wrong way through them.

To put it simply, dont fuck around with generators. Doing it wrong could kill a lineman, kill you or start a fire in your house. TYransfer switchs arent all that much, it wouldnt hurt to get it done right.

How is the switch installed?
I don't use the dryer circuit at all, could this be used if needed?

EDIT
Looks like it installs at the service panel?

http://www.northerntool.com/we...70_200196674_200196674

Absolutely it does.

Take a look at this manual for a very basic example of a manual transfer switch hookup:
http://gen-tran.com/assets/pdfs/MTSinstall.pdf

If you understand how to do everything and why you have to do what's in that manual, you may be able to tackle the project. Otherwise, call an electrician.

 

[AlienCraft]

Originally posted by: bctbct

Originally posted by: BigJ

They added the exception in the 2005 NEC. Here is the exact wording:

Exception: Temporary connection of a portable generator without transfer equipment
shall be permitted where conditions of maintenance and supervision ensure that only
qualified persons service the installation and where the normal supply is physically
isolated by a lockable disconnect means or by disconnection of the normal supply
conductors.

In other words, you better have your shit in order if you do it. It's not really meant for Joe Blow to hook up his genny without a transfer switch.

Dont you love how they can't ever seem to put anything in plain english that everyone interprets the same way.

Qualified persons is debatable, I would interpret the bolded areas to be the main breaker.

WElll, in codes, it's the Agency having Jurisdiction that makes that call. Checking the DEfinitions page of the NEC, you'll find that BREAKER doesn't = CONDUCTOR. FURTHERMORE, the NEUTRAL must be considered a "Current Carrying Conductor"{ by the very nature of AC power. Up here in NorCA, that could be PG&E, SMUD, OR the County Building Depts. BUT in most cases involving power lines , the County defers to the Utlity as to what they let fly.
And they don't like those "hotplug" connections, fer sure.

 

[bctbct]

BigJ said

Adding a standby generator to the electrical system of a home, farm or business requires a suitable transfer switch to disconnect the electric loads from the power supplier's utility grid. This is a requirement of the National Electrical Code (see NEC Article 702-6) and all electric power suppliers, for two very good reasons: (1) it prevents the back flow of current into the utility's lines during an outage, which could electrocute linemen working to restore power; and (2) it prevents damage to the generator when regular electric service has been restored, which can destroy the generator.

This exception was added in the 2005 Code. This exception provides requirements for
the connection of loads to a generator without the use of a transfer switch, where the
installation is under the supervision of qualified service personnel. Such applications
often occur when necessary for equipment maintenance or breakdown or when there is
an extended power outage. In such instances, a portable generator can be brought to a
facility and connected to the existing distribution system. The supervision by qualified
personnel is critical to ensuring that a dangerous backfeed condition is not created by
connecting the generator to the system without the benefit of transfer equipment.

You already addressed this for me.

AlienCraft said

Unless you're in Mexico,us folks in the United States, electrical codes are goverend by the NATIONAL Electrical Code, and I will gurantee you that connecting a generator in the manner described via a 220volt outlet being fed in reverse is not acceptable anywhere.
Furthermore, I challenge you to prove otherwise.
If there is a plug with a hot & neutral reversed, that neutral line is now feeding back into the system, the voltage present at the generator, THAT is how a backfeed gets around a standard main breaker thrown OFF.

SEE ABOVE

 

[AlienCraft]

Reliance Controls of Racine Wis.
A massive array of transfer switches.
Easily installed by any homeowner with Home wiring Experience.

Do everyone a favor and quit with the BS connection.
See my sig for motivation.