| Click to Post a New Message!
Page [ 1 ] |
|
|
|
PTO Generators Observations
Voltage, current and the related horsepower is the same in Metric or Imperial measure (he says with his tongue firmly planted in his cheek).
Best of luck.
|
|
 Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
A very good question Harvey....
Best the Government has figured so far is that there is DEFINITELY an inverse relationship involved.
It seems that when the temperature or the voltage goes down, the population goes up, there IS however about a nine month delay in the process... they estimate the power failure last fall alone will result in about 15,000 new Metric people.
All the usual fine print applies regarding liability resulting from spilled coffee or falling out of chairs from excessive laughing. Tissues NOT included. Premium membership required to access punch lines.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
In our area the electrical authority have a VERY dim view (no pun intended) of improperly wired generators.
A neighbour up the road from me discovered this the hard way last winter, during a storm a car took out a pole and brought down lines which caused an outage affecting most of this half of the township.
He thought nothing of it and sparked up the generator. A few minutes later a line crew came down the road checking the lines, when they got to his place a guy went up in the boom and used a special cutter to drop the leads coming from the pole to his house, then just drove away.
When he called the office they told him the line crew had discovered that his house was improperly wired and he was back-feeding the grid. They told him that he needed to hire an electrician and fix the problem, then call and they would have to do an inspection before they could re-connect him to the grid.
Unfortunately for him, the re-inspection required his entire house to meet TODAYS standards.
His entire house had been wired without grounded receptacles and the panel was only 60 amp, so it had to be upgraded to 100 amp minimum.
He was grumbling to me that it cost him thousands, I told him he was lucky, it could have cost someone their LIFE.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
Ontario has amongst the tighest electrical safety regulations of any jurisdiction in North America.
Unfortunately we also have a great number of very old electrical services still in operation, and oddly enough our reg.'s don't require that existing services be upgraded.
When that is combined with things like the big ice storm a few years back, the great blackout in the summer of 2003, and the Y2K scare the result is that we have a lot of generators hooked up to painfully out-dated wiring.
I have a neighbour at the cottage who regularly fires up a 25KW diesel genset and feeds it into his KNOB & TUBE wired 100 year old post & beam cottage!!!
Some people are just plain stoooooopid.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
Dave is right. Denwoods method could likely kill an unsuspecting linesman who failed to carefully check all three conductors assuming the lines were safe.
In fact this is EXACTLY the methgod used by my neighbour that led to his electrical service being disconnected by the utility.
In almost all cases the "mains" in a house are only double pole single throw switches, this means only the two "hot" wires are disconnected, this leaves the neutral side and the ground bonded through to the incoming lines. They are the potential problem.
If under these circumstances you had a faulty wire somewhere you could, using the ground and neutral conductors electrify the lines in front of your house.
This is what electrocutes linesmen working on "dead" lines.
The other hazard is merely burniung down the house or wrecking some expensive electronic equipment. Since you are tapping into the 220v. side of the wiring and depending on luck to have a balnced split between the two legs of the 220 wiring you run the risk of having all (or even most) of the load on one side of the generator. This could lead to very low voltages and much higher than normal current flowing.
The ONLY safe way to use a generator is to either plug the desired item directly into the genset, or have a proper transfer panel, a switch which will COMPLETELY isolate the generator and all the load to be transferred to it from the incoming utility lines.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
You are both correct, the electrical safety reg.'s in Canada are amongst the strictest in the world.
Here we must have a transfer switch which a) breaks the neutral bond between the generator supply and the utility's supply lines, and b) it must be of a "break-before-make" design, in other words it must open all 3 circuits from the utility's lines BEFORE it can connect to the generator. They also MUST be capable of transferring their full rated capacity UNDER LOAD.
The ground wire is a moot point since one conductor cannot form a circuit, especially when it's grounded anyway.
Most transfer switches here are also equipped with a neutral bond break delay to ensure there is no out of phase issues created by the transfer switch.
IMHO, a 2 pole transfer switch is just a big poke waiting to happen to someone, likely an unsuspecting linesman.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
No the neutral leg is bonded to the ground here also.
However, as I'm sure you are painfully aware, electricity takes the path of least resistance. If there is a bach-feed situation there is a 220 V. potential on the neutral out to the transformer which will, as mentioned, step it up to line voltage.
If an unsuspecting linesman becomes the conductor to complete the circuit he gets a big poke.
Thats why the neutral MUST be disconnected here to prevent potential back-feeding of the grid.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
There is absolutely no difference, that's exactly the problem.
It is so easy and simple that most people do it exactly that way, make up a cord with a male plug on each end and away they go.
In some areas it is even borderline legal.
However, it is not safe or smart.
It is also difficult to balance the load properly doing it that way since it is purely chance which side of the supply the load happens to be on.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
Steve, I suspect that it is as you say, also the NEC in the US doesn't require it. They assume that the electric utility has done it's job and everything at the transformer, etc., is wired the way it's supposed to be. That is a potentially fatal assumption.
Say for example the power outage, the reason for running the genset, is a result of a lightning strike. If the lightning strike destroyed the neutral conductor on the primary side of the transformer then you could have not only substantial potential on the lines, but you could in fact also have lit up any telephone or cable TV wires that not well grounded, even if they are well grounded they could form a return for the primary circuit.
Try searching on Google or Yahoo for "stray voltage" or "stray current", there is mountains of data out there on this subject.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
Denwood, there is no transformer connection to the neutral, in fact the neutral is bridged past the transformer.
A part of properly installing transfer switch is making sure that the feed and the load are balanced, ie, an equal amount of current on each leg of the 220V. feed from the genset.
A typical house service panel is not wired with a balanced load in mind, usually it just wired up according to which wire the electrician happened to grab next. If you were to just feed pull down the mains, and backfeed a 220V. circuit like the dryer plug, you could have a balanced load, or you could have the entire load on one leg. Thats the problem.
However, many, many people merely re-arrange the load at the service panel to accomplish a balanced load and then backfeed it from a generator. Several people in my area do this, some even use a SP/ST switch box to disconnect the neutral from the service connection which at least makes the setup a little safer.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
I think the source of most of the confusion around this subject is that most people, including electricians, feel there is no electricity in the neutral wire since it is grounded, in fact nothing could be farther from the truth.
First of all let me say, that in ANY circumstance where the neutral is still connected to the utility company's grid, the potential risk exists, whether or not the mains are open.
Maybe if I give the 'big picture' it will make it clearer. The phenomenon is called stray Voltage.
The electrical utility company causes the problem of stray voltage when they connect the neutral on the primary side of the transformer to the neutral on the secondary winding of the transformer. Why do they do this? Because this is the standard connection specified in the National Electrical Safety Code (NESC) which governs the utilities. The National Electrical Code (NEC), which covers all wiring, requires that the secondary neutral be hard wired to the buildings water system, structure and electrical ground rod.
Therefore, the voltage level of the building structure and water system is elevated to the voltage level of the primary neutral conductor on the utilities electrical distribution network. This voltage can be significant and is the primary cause of Stray Voltage.
The origin of the stray voltage problem lies in the fact that Electrical Utilities do not make a distinction between the function of the Neutral (the grounded conductor) and a Ground. The Electrical Utilities in conjunction with the IEEE has developed the National Electrical Safety Code (NESC). This code requires them to ground the primary neutral conductor at least four times per mile that they distribute electricity. Electrically, the ground rods are actually resistors ranging from 10 to several hundred ohms. The actual resistance depends upon the moisture content and conductivity of the soil. In other words, the utilities are forced to deliberately design their systems to use the earth as a secondary neutral conductor.
The voltage on the primary neutral increases as the distance from the substation increases. Each ground rod tends to reduce the voltage by diverting some of the neutral current into the earth. The current splits between the neutral wire and ground rod in accordance with ohms law. The primary neutral voltage at the end of the distribution line can be 20 volts or more depending on the combined load on the distribution line and the conductivity of the earth. The NESC requires the Electrical Utility to connect the primary neutral to the secondary neutral on each transformer serving a customer. The National Electrical Code (NEC) which governs all wiring requires that the secondary neutral be grounded to the water pipes for every building being served. Effectively the SAFETY CODES require us to hard wire our water system directly to the neutral on the primary distribution side of the transformer.
However, when you connect a generator and put power to the house's wiring, the 220V. gets split, there is 110V. between each of L1 & L2 and the neutral, and 220V. between L1 & L2 directly, but if the conditions are right, or maybe wrong is a better word, there is voltage potential in the neutral itself. If that neutral, which is a continuous conductor all the way through the grid, gets connected by a person's body, like a linesman who thinks he's working on a 'dead' circuit, or telephone wires, or cable TV wires and it becomes a better conductor, guess what? Somebody gets a shock. In a worst case scenario it can kill.
The bottom line is anytime there is potential in the neutral beyond your house it's a bad thing.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
AB, you are getting very close, there are risks of grounding a portable genset, it is safer to use the neutral to ground the genset into the house system. It is NOT, however, safe to leave the neutral connected back to the grid from the house when the house is being back-fed by a genset. There is a very real risk of creating a potential in the neutral and causing a hazard for anyone working on the supposedly dead wires in the grid.
KY, a very good point about meter tampering, although I would think the bigger hazard would be from taking the meter off it's base and having all those live leads open to anyone who wanders by.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
Ann, with all due respect, I think you need to re-read my post and the link I posted.
I said "... there are risks of grounding a portable genset, it is safer to use the neutral to ground the genset into the house system. It is NOT, however, safe to leave the neutral connected back to the grid from the house when the house is being back-fed by a genset.".
I did not, nor did I intend to, say that the house & genset should NOT BE grounded. To open the neutral without leaving an adequate ground for the system would be foolish, and an open invitation for electrocution and or a fire.
What I was trying to get across was that there is a very real danger in leaving the neutral connected back to 'the grid'.
The only safe way to do it would be to have the service panel grounded directly such that when the neutral is opened the system is still grounded.
When the NEC was written it was not worded with the proliferation of gensets that we have today in mind.
Here in Canada, where the electrical safety regulations are amongst the strictest in the world, NOT opening the neutral back to the grid is a violation.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
Some transfer switches available up here feature a small bulb like those found on circuit testers which lights up to indicate when there is power available from the grid. Other more expensive systems on permanent generator installations are switched electrically, when the electricity is off form 5 seconds, the switch disconnects the service and starts the generator, when the power comes back on, the switch turns off the generator and returns the service to the grid connection.
Our electrical safety code requires a main switch and fuses or breakers rated for the full capacity of the service panel.
In other words, we have the meter, then (usually, the present minimum) a 100 amp switch, then a pair of 50 amp fusible links, then the service panel itself.
This is the problem, it is too easy to merely flip the main service switch and plug a genset into a dryer or welder recepticle.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
PTO Generators Observations
Electricicty will ALWAYS take the path of least resistance. Nobody will argue that.
What most people fail to realize though is that it will rarely take ONE SINGLE path.
When you power a house by putting 220v. from a genset into the service panel, then power 110v. loads by 'splitting' the 220v. using the neutral and one leg of the 200v. you now have converted the neutral into a current carrying conductor.
Period.
The part most people cant get their head around is a concept known as "neutral-to-earth voltage". Do a little research on it, the answers you will be find are astounding to most people.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
Page [ 1 ] | Thread 72825 Filter by Poster:
10 | 2 | 1 | 1 | 2 | 9 | 6 | 2 | 11 | 1 | 1 | 7 | 2 | 15 | 6 | 2 | 4 | 3 |
|
()
Picture of the Day
rockingo
Unanswered Questions
Active Subjects
Hot Topics
Featured Suppliers
|
Gas Generator Weather Protecti
01-05-2004, 10:52 
Digg It 
Del.icio.us