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Please help before I kill someone

BigAl

Gone But Not Forgotten
SUPER Site Supporter
I do not know what I am doing wrong . I recently purchased a whole house generator . Untill I decide which transfer switch I want , I have been back feeding through my 220 volt 50 amp welder circuit . I shut off the sub panel main disconnect so I do not back feed into the grid system .The minute the grid power comes on the generator dies . I have a feeling it is getting grid power from somewhere . What am I doing wrong ???????
 

snow dog

New member
when the power goes off,, do you disconnect the Main breaker so that there is no path from the PUC lines . Normally the main breaker is just in the Black line but the common ( white is available to carry power) if everything is correct in the power boxes. The Transfer switches I have seen disconnect both white and Black wires so that there is not chance of any backfeed.
 

BigAl

Gone But Not Forgotten
SUPER Site Supporter
when the power goes off,, do you disconnect the Main breaker so that there is no path from the PUC lines . Normally the main breaker is just in the Black line but the common ( white is available to carry power) if everything is correct in the power boxes. The Transfer switches I have seen disconnect both white and Black wires so that there is not chance of any backfeed.


Thats what is strange . The main breaker in the sub panel shuts down all grid power . I am to the point that I am afraid to use my back up system for fear of shocking some poor lineman . Maybe nothing is wrong , but what is killing the generator when the grid power comes back on line ????
 

XeVfTEUtaAqJHTqq

Master of Distraction
Staff member
SUPER Site Supporter
when the power goes off,, do you disconnect the Main breaker so that there is no path from the PUC lines . Normally the main breaker is just in the Black line but the common ( white is available to carry power) if everything is correct in the power boxes. The Transfer switches I have seen disconnect both white and Black wires so that there is not chance of any backfeed.

That is my understanding too.
 

DaveNay

Klaatu barada nikto
SUPER Site Supporter
OK Thanks guys , tomorrow I will check the white wire .

You also have to make sure you have a good ground on both systems. Remember, voltage is measured as a difference to another voltage, the two 120V branches are measured relative to ground (240V relative to each other). If your generator and main feed do not both have good grounds, there can be voltage potential between them, and the electronics of the generator might be shutting everything down as a protective action.
 

XeVfTEUtaAqJHTqq

Master of Distraction
Staff member
SUPER Site Supporter
From another forum I'm on:

http://www.canadiangunnutz.com/forum/showthread.php?t=568854&page=7
In a 220 volt electrical residential service you have 2 110 volt lines and a neutral coming into the house. Each one of these 110 volt lines carries 110 volts when measured to ground or to the neutral. The potential between the two 110 volt lines is 220 volts when measured from line to line.
Let's say your wife or your daughter is running a hair dryer on one circuit and that circuit is fed from one of those lines, and that hair dryer draws 8 amps.
Let's also say you are running a sander out in the garage and it draws 5 amps and it is fed from a circuit on the other line. The difference is 3 amps. The neutral carries the unbalanced load of 3 amps. If when you cobble up a system (however you choose to do it) and you do not break the neutral in your panel as well as the 110 volt lines, then the unbalanced load from the generator feeds the power authority's lines.
Now when the lineman is out on the pole or in the bucket
trying to fix the problem often in inclement weather or in the dark or both, there is a good chance he is going to take a wallop off that neutral.
What this all boils down to is this, "wiring is not a hobby, hire a professional."
Electricity comes to your home via a very complex grid but for the sake of simplicity we'll start with the 2400v to 16,000v (called line or primary voltage) distribution voltages common in rural and suburban Canada. (there are lots of other voltages and systems, but this is typical).

The primary is stepped down through the transformer (pole or pad mounted) to the 120/240v used in the home.
When the power goes out the automatic transfer switch opens the line side of your household main and closes another switch that is wired to your genie and whatever you are going to power up. A manual switch does the same thing, only is operated...manually.


We'll use the dryer plug example, but this basically applies to all the hack-rigged jobs. By the by a dryer plug is generally only rated to a max of 40 amps, it won't power everything in your house. When the dryer plug set up is powered up with the generator the 120/240v that is now partially powering your home also goes through the main switch (because the homeowner forgot or just plain didn't know to open it, even with it open, the neutral connections are still there, thank you Gerald) and out to that transformer that feeds you and your neighbours. Distribution transformers are both step-up and step-down. That means the household voltage is now feeding the can and primary voltage (remember the 2400v to 16000v) is now coming out and it travels a long, long way.

So those lines that are laying on the ground in the storm can now be live and stumbled across by any one. The line crew down the way is out to do repairs and is unaware of the illegally wired generator (they have killed before). Partial voltage or "brown out" type voltages are feeding homes and causing damage to any kind of household equipment. (see my previous post for what does happen when the line crew snaps a set of grounds on this type of set up)
 
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