Joshua
I'm researching the installation of a transfer switch on my home. All the switches I see talk about pre-selecting some number of circuits and re-routing them through the breakers in the switch box. What I don't understand is why the electrician can't just install the switch leading into the main breaker box such that the generator was feeding the entire house. The genny isn't nearly big enough to run the whole house, but in the event of an outage, I could selectively switch on circuits that I wanted to use, without having to pre-decide which ones I did or didn't want.

Is there some obvious reason why what I'm describing isn't done?

Thanks.
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hoghead
The short answer is the National Electric Code
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Joshua
hoghead;9341 wrote:
The short answer is the National Electric Code


Could you tell me a little more?
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mastr
Joshua;9344 wrote:
Could you tell me a little more?


You will need a service entry rated manual transfer switch ahead of your main breaker to do what you describe. I had one for years before I finally bought an automatic switch.

Here is a 200 amp example- [url]http://www.harborfreight.com/200-amp-generator-manual-transfer-switch-42163.html[/url]

There are other brands besides CH, Square D and Ronk make them too.
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Joshua
mastr;9346 wrote:
You will need a service entry rated manual transfer switch ahead of your main breaker to do what you describe. I had one for years before I finally bought an automatic switch.


Thanks a lot. That seems to fit the bill.
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Skip Douglas SkipD
Joshua;9348 wrote:
Thanks a lot. That seems to fit the bill.
As was alluded to above, while the transfer switch hardware idea "seems to fit the bill", the National Electrical Code - since the 2008 version - requires a standby generator to be sized to be able to power EVERYTHING that it is [U]automatically[/U] connected to. There is no allowance in the calculation for someone turning off some loads manually, though there can be automatic load-shedding devices used. This is why mastr included the word MANUAL in his description of the transfer switch he had used in the past.
Skip Douglas
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Skip Douglas SkipD
mastr;9346 wrote:
Here is a 200 amp example- [URL]http://www.harborfreight.com/200-amp-generator-manual-transfer-switch-42163.html[/URL]
Is that switch truly service-entrance rated? The advertisement does not say that it is, and I thought that to get that rating it would need a service-entrance disconnect with an over current protection device.

I'm not a formally trained and licensed electrician, but I'm always trying to learn more.

Thanks.
Skip Douglas
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mastr
SkipD;9350 wrote:
Is that switch truly service-entrance rated? The advertisement does not say that it is, and I thought that to get that rating it would need a service-entrance disconnect with an over current protection device.

I'm not a formally trained and licensed electrician, but I'm always trying to learn more.

Thanks.


The CH switch was the first one Google found. All I can say for sure is that there are several of them installed locally, between the meter base and main breaker. I have a diagram from my power co. showing a blade type switch with no apparent OC protection, so it must pass here anyway. I asked about it, got an odd look and the reply "that is what the transformer fuse is for."

Here is one switch that I know is SE rated.
[url]http://www.gen-tran.com/eshop/10Expand.asp?ProductCode=R2022[/url]

Of course, it costs more, but IMHO is a better switch.
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Joshua
SkipD;9349 wrote:
As was alluded to above, while the transfer switch hardware idea "seems to fit the bill", the National Electrical Code - since the 2008 version - requires a standby generator to be sized to be able to power EVERYTHING that it is [U]automatically[/U] connected to.


I may not have been clear enough in my original post. I'm not thinking of using a standby generator or an automatic transfer switch. This would be for manually hooking up a portable generator in the event of an outage. I realize this forum focuses more on automatic standby generators, but it was the only generator forum that I could find, so I wanted to ask.

Does that change things any?
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genme
Joshua;9352 wrote:
This would be for manually hooking up a portable generator in the event of an outage. I realize this forum focuses more on automatic standby generators...
Actually, there is a portable generator section of this forum that can be accessed from the main page (scroll down a bit.) Others here are more qualified to answer your most recent question than I am, so I'll defer to them.
Model 5875, Nexus controller, 999cc Engine, 20kW LP, 2011
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Skip Douglas SkipD
Joshua;9352 wrote:
I may not have been clear enough in my original post. I'm not thinking of using a standby generator or an automatic transfer switch. This would be for manually hooking up a portable generator in the event of an outage. I realize this forum focuses more on automatic standby generators, but it was the only generator forum that I could find, so I wanted to ask.

Does that change things any?
The problem that you are facing deals with the utility power service and the national and local code rules that apply to it.

If you want to switch the power in your entire main breaker panel to generator power, you would probably need to have a "service-rated" transfer switch wired in between your utility power meter and the current "service-entrance panel" which, in most cases is the main breaker panel in a typical home. You would have to know the codes that apply in your area to determine whether or not you can do what mastr was suggesting with a simple switch.

Having the transfer switch be manual instead of automatic would possibly exempt you from some of the rules about generator sizing relative to the loads it could power.

If that simple installation is not allowed (and it is not allowed where I live), you would need a transfer switch that has a service-entrance rated disconnect in it for the utility power. You would quite likely have to re-wire all of your equipment ground wiring to separate it from the neutral wiring. In addition, your local codes may prevent you from doing what you want simply because of the size of the generator.

By far, the simplest solution would be a relatively small and relatively inexpensive manual transfer switch which would be fed by a dual breaker in your main panel for the "utility" energy side of the transfer switch and a place to plug in a cable from your portable generator. There would be breakers in the transfer switch for your emergency loads, requiring you to move the wires that presently go to breakers in your main panel. You would simply have to determine which circuits to move and you would not have the luxury of a "whole house" installation.

My best suggestion is for you to contact your local electrical inspector and get a written ruling from him/her as to what would be acceptable for your generator installation and whether or not he/she would allow you to do the work yourself.
Skip Douglas
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Joshua
SkipD;9355 wrote:
You would quite likely have to re-wire all of your equipment ground wiring to separate it from the neutral wiring.


That may be a deal-breaker right there, since part of the appeal of the single-switch solution is the potential simplicity of the install. Is the issue there related to "floating neutral" vs. "bonded neutral" in the generator?

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You would simply have to determine which circuits to move and you would not have the luxury of a "whole house" installation.

My best suggestion is for you to contact your local electrical inspector and get a written ruling from him/her as to what would be acceptable for your generator installation and whether or not he/she would allow you to do the work yourself.


Indeed.

Thanks very much for the detailed reply.
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Skip Douglas SkipD
Joshua;9357 wrote:
That may be a deal-breaker right there, since part of the appeal of the single-switch solution is the potential simplicity of the install. Is the issue there related to "floating neutral" vs. "bonded neutral" in the generator?
The bit about separating the equipment ground wires from the neutral wires is a requirement of the National Electrical Code. The rule is that there is only one place where equipment ground wires and neutral wires are to be bonded together. That place is the service entrance panel - the first panel where the utility power feed (beyond the meter) is terminated.

In my installation, the utility feed was re-routed from the main breaker panel to my new service-rated transfer switch panel. As a result, I had to un-bond the neutral bus from the panel itself and remove all equipment ground wires from the neutral bus. All of the equipment ground wires were then routed to a new ground bus which was bonded to the panel.
Skip Douglas
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genme
SkipD;9358 wrote:
All of the equipment ground wires were then routed to a new ground bus which was bonded to the panel.
Only one of 4 electricians that I had here suggested this idea (a good idea in my non-electrician mind.)

All the other electricians suggested moving all the neutral wires to the existing bar on one side of the panel, and all the grounds to the existing bar on the other side of the panel. In our panel, this would have required more time, moving breakers, and extensive use of pig tails for neutral and ground wires which were not long enough to reach.
Model 5875, Nexus controller, 999cc Engine, 20kW LP, 2011
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VHF
The least expensive way to be able to power any loads in the house would probably be to use an interlock kit if one is available for your main breaker panel.

A 240VAC double breaker is installed in the upper right corner of the panel and is used to "backfeed" power from the generator to the panel. The interlock kits prevents the generator backfeed breaker and the main breaker from being on at the same time--an illegal and hazardous situation.

[url]http://www.interlockkit.com/[/url]

You would need to verify with your local inspector that this type of product meets transfer switch requirements in your area.

You would need a generator inlet installed on the outside of your house, wired to the new 240VAC generator backfeed breaker.

To use the generator, connect it to the inlet (using an appropriate 240VAC generator cord), start up the generator, go inside and switch off your main breaker, switch of most/all of your individual breakers, switch on the generator backfeed breaker, then switch on individual loads being careful not to overload the generator.

You can power anything in the house that doesn't exceed the capacity of the generator--just not all at the same time!
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mastr
SkipD;9350 wrote:
Is that switch truly service-entrance rated? The advertisement does not say that it is, and I thought that to get that rating it would need a service-entrance disconnect with an over current protection device.

I'm not a formally trained and licensed electrician, but I'm always trying to learn more.

Thanks.


On a recent visit to HF, I looked inside the subject switch. It says, “suitable for use as service equipment” inside the lid, and bears a UL mark. It does not contain any fuses or a circuit breaker.
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ceb58
SkipD;9350 wrote:
Is that switch truly service-entrance rated? The advertisement does not say that it is, and I thought that to get that rating it would need a service-entrance disconnect with an over current protection device.

I'm not a formally trained and licensed electrician, but I'm always trying to learn more.

Thanks.


mastr;9857 wrote:
On a recent visit to HF, I looked inside the subject switch. It says, “suitable for use as service equipment” inside the lid, and bears a UL mark. It does not contain any fuses or a circuit breaker.


Skip, it doesn't require over-current protection but any I have installed the inspectors have taken the stance that as long as it is outside the building its OK.
From the 2011 NEC

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VI. Service Equipment — Disconnecting Means
230.70 General. Means shall be provided to disconnect all
conductors in a building or other structure from the service entrance
conductors.
(A) Location. The service disconnecting means shall be installed
in accordance with 230.70(A)(1), (A)(2), and (A)(3).
(1) Readily Accessible Location. The service disconnecting
means shall be installed at a readily accessible location
either outside of a building or structure or inside nearest the
point of entrance of the service conductors.


Even though it dose state inside nearest the point of entrance you have to deal with
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(B) Additional Service Disconnecting Means. The one or
more additional service disconnecting means for fire
pumps, emergency systems, legally required standby, or optional
standby services permitted by 230.2 shall be installed
remote from the one to six service disconnecting means for
normal service to minimize the possibility of simultaneous
interruption of supply.
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MASTERTECH-MW
The Second Is.in Auto Mode It Would Keep Shutting It Down From Overload....and If Your Not Home.there Is No Telly What Can Happen......why Not Put A Whole House.usually 20kw And Just Get A Transfer Switch With No Breakers
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ceb58
MASTERTECH-MW;9869 wrote:
The Second Is.in Auto Mode It Would Keep Shutting It Down From Overload....and If Your Not Home.there Is No Telly What Can Happen......why Not Put A Whole House.usually 20kw And Just Get A Transfer Switch With No Breakers


Not that simple. 230.70 NEC requires a service disconnect before the ATS or the ATS be service entrance rated ( disco./ocp) built in to the switch.
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