The electrician installed five 3-way switches next to the main panel to switch between the utility and a generator. I am used to seeing a generator transfer switch or a dedicated panel for the generator circuits. Are these switches rated for this type of duty? Is this OK?
well a typical wall switch should be able to handle at least 15 amps which is roughly 1500 watts.
How much power are those generators drawing , and what kind of fuse or breakers.
Is this commercial?
This is residential. It is my understanding that generator switches are designed to completely break contact with the first terminal before the making contact with the second terminal. This keeps the lineman from getting zapped (that and a little common sense). I am not sure a typical 3-way light switch works the same way.
I didn’t see any fuses or breakers outside of the main panel. Most generators are fitted with breakers. Should there be additional breakers for the generator circuits?
I did not see the generator. It was locked in a shed that I did not inspect. The only evidence of generator wiring was what you see in the photo.
Thats is why I would in this case ,defer to a certified electrician to inspect the generator system.
You had no access.
This is something you may not run into alot of .but sounds worth studying now that you know it may come up.
Was it a auto start?
Point wire to the circuit being served and the two travellers to the two separately derived power sources… Hmmmmmm. I am guessing, but the only thing might be the fact that they are not all switched at once with one throw. Don’t have the codebook with me, but now I have something to look up… Kind of a kool application tho!
Normally If a auto start it would control the panel Using switches inside the panel normally open , when the power goes off they close then they send a signal to the generator to start when the power comes back on it shuts the generator off ( this is all timed through a circuit panel similar to the big guys switch gear in large buildings. I wouldn’t depend on light switches and that are manual controlled to many things can happen. Other option is with the portable generator is the breakers are tandem either generator or power (One throw ) so you can not send power to the lineman.
PS i hope you can follow this , it goes through my head but doesn’t follow down to my fingers. lol
I don’t know about you all but my agreement does not include generators and their switching devises so it would get deferred to a qualified electrician regardless whether it was accessible or not.
Very true
Power company will not inspect the auto start here even
Same in my area - funny how their lineman are the ones at risk, yet they neither confirm or deny…
This is a very dangerous set up. A critical thing regarding transferring circuits to a generator is that the neutrals have to change sources and also be isolated from the power company.
Everything in this sentence is utter and complete nonsense, not to mention plainly incorrect. The neutral does not have to change sources. It may, but seldom does. When you switch the neutral also, you bring in a whole other set of complicated requirements, so it’s almost never switched without good cause. From what I can see so far, there is nothing dangerous pictured.
I fully concur with this. The neutral needs to be isolated from hydro utility power and it’s most likely not happening with the switches. Switches are not meant to be used as transfer switches, you can make it happen but really you need a three pole transfer switch to cut both lines and neutral at the same time if you’re using a 120/240Vac generator.
Like all electrical equipment they all have their purpose and a transfer switch is the proper device to use, or a power relay to transfer at best, in an emergency backup system. Did he install a relay control box somewhere? Using a switch to control a relay or a contactor would be ok.
This would not pass an electrical inspection if just switches are used to transfer I’m sure. If your house goes up in flames as a result of this setup your insurance company probably won’t cover either.
Mike
I beg to differ on your response.
If you don’t break the neutral a potential can occur at the pole or a potential can hit your emergency backup system and damage it.
Picture maybe a lineman shorting out the lines to your house accidentally during a repair. Will there not be current back feeding into the neutral to your power system?
What if the generator shorted out or you had a leakage from a breakdown in insulation and or you had a defective breaker that didn’t trip, would it not send current out to the lineman working on your mains?
Many accidents happened during the great ice storms we had where generators blew up as a result of improper isolation and bonding methods. When hydro utility power resumed of course people had generators wired directly onto the mains or through a breaker and forgot to turn the main breaker off but the other reason was accidents. In order to have a safe system one must break all three conductors in an emergency backup system. This will ensure that at no time will there be an accident.
The generator emergency sub panel should only see the generator neutral when in use and the same goes for hydro utility power.
His emergency circuits are on the load side of the switches. The generator lines and main distribution breaker lines are feeding the travelers of the three ways.
Mike
Honestly I can’t see the images real well so I wont comment on them. I would defer to an electrician to look at them up close if you have a concern. As for the comments about the switched grounded conductor…( if I may ) in nearly 99% of all applications with a generator we have a transfer switch that does not switch or disconnect the grounded conductor…please read the definition of a SDS in the National Electrical Code and understand that while some transfers switches will switch the grounded conductor ( a true SDS ) some transfer switches do not and they are no more dangerous.
So unless I am missing something because I ( to be honest ) dont really want to read all the text…I will say this I have been teaching seminars for many years now and I can promise you not all generators switch the grounded conductors at the transfer switch…So while we can throw reason into the MIX…the National Electrical Code does not mandate the switching of the grounded conductor in it’s application.
Now lets not try to mingle NEC 700, 701, 702 and 705 into the basic understanding of what constitutes a seperatly derived system as Marc is speaking of. If the tranfer switch is 3 pole with a common neutral ( grounded ) termination then it is not considered an SDS…if it is a 4 pole transfer switch with a switched neutral ( grounded ) conductor then it is a SDS…
**Separately Derived System.
**A premises wiring system
whose power is derived from a source of electric energy or
equipment other than a service. Such systems have no direct
electrical connection, including a solidly connected
grounded circuit conductor, to supply conductors originating
in another system.
Thus…again 99% of all the transfer switches I see ( and I see alot as a Munucipal Inspector ) do not meet the requirements to be considered a SDS…this they must be wired accordingly and the equipment grounds, grounded conductors and so on must be sized accordingly. Are you saying all the manufactures are wrong and the UL listing on the transfer switches is a massive error in listing…I think you understand what I am saying, we are not speaking theory here but how it is written as a minimum standard. Minimum National Electrical Code Standard…not Canadian Standard as I would not have a clue on theirs.
Hi Paul,
I envy that you found the time to acquire such a vast level of certification regarding electrical systems and the field in general.
I too know a bit about electrical, generators and installations. I’m a master electrician in the province of Ontario with 30 years of experience in the electrical industry, and I’ve installed over 50 generators in recent years. I also have a diploma in electronic controls. I was offered a chance to teach ESA (Electrical Safety Authority) inspectors and master electricians regarding installation of alternative power systems from generators, solar, grounding to bonding and I chose not to as I had a busy life with 6 children.
The topic here started with “Are these generator switches ok?”
As an electrician I don’t need to look at the switches up close to see that this is not an approved transfer switch system, therefore the answer to his question is no.
I agree that most fixed 3 phase standby generator installs do not switch the neutral and it’s not mandated by the NEC except in special circumstances. This type of 3 phase system can use a 3 pole MTS or ATS to break the lines. One instance where the game changes is with portable generator systems, 3 phase or single phase. Many people use portable generators and manual switching in an emergency power outage, this I assumed was the case here. A portable generator supplying 120/240 Vac power from a cord and plug connected to a transfer switch to feed a premise wiring system (say via a male flanged inlet receptacle outside or too the three ways in this system from a junction box) is considered to be a separately derived system. This is what most people do in an outage as many don’t have fixed stanby systems with automatic transfer. They put the generator outside on the ground and connect to a 3 pole transfer switch (3 poles 3 throw for L1-L2-N) using the methods I mentioned earlier to feed circuits in a emergency circuit sub panel. When 3 wire 120/240 Vac generators are of a portable nature, and most are, a load neutral along with its phase conductors when transferring loads between power sources must be switched. If ground fault protection is not required, the portable generator is not connected via a cord and receptacle attached from it, and the generator is fixed the generator neutral can be solidly connected to the service neutral. In this case a 2 pole (DPDT L1-L2) transfer switch can be used.
So if you use a portable generator, 3 phase or single phase, it has to be converted to a fixed system bolted to concrete (isolated from earth ground) have no generator frame bonding and no ground fault system to make it a non SDS. A 120/240 Vac portable generator should have a 3 pole MTS or ATS as it is a separately derived source and the neutral is grounded at the generator. The same holds true for a 3 phase 4 wire system having to use a 4 pole MTS or ATS. A neutral conductor shall be bonded to the generator frame if the generator is a component of a separately derived system (portable).
A four-pole ATS is better than a three-pole switch from a maintenance and safety perspective. With the 3 pole ATS, if the main service is taken offline for maintenance or any other reason and the standby generator is running to serve the critical and life safety loads, the standby generator is still relying on the main service ground connection to the neutral for the return path of any ground fault. If somebody is not aware of this grounding configuration, and maintenance is performed on the main service ground when the service is offline and the standby generator is running, the standby generator would no longer be properly grounded. This could be a serious safety concern and could potentially allow fault currents to flow without tripping the over current protective device.
Mike
My last generator install this winter.
A non SDS. I do have pics of an SDS using a portable generator, with manual transfer and flanged inlet receptacle to supply the transfer switch from a generator outlet that I will post here soon. The wiring of the system may be useful to someone in the forum.
http://powerelectricsystem.com/2.jpg
Mike,
Keep in mind my responses are general in nature based on the reply to the question involving a comment made by marc and answered by others. There are complex issues when dealing with generators as a whole. I did not address the switches is because others have addressed them.....I was dealing more with responses to marc's statement which is correct in nature.
In a feedback type senerio you will always be safer in theory by removing the ability for the grounded conductor to connect back to te system…but the NEC does not prevent this situation for the most part in normal applications…
Lets remember now that HI’s do not extend into the level of this knowledge under their SOP…but I guess some will disagree.
Hi Paul,
I get the plan on the HI-SOP and you’re right.
I need to bring this up.
Marc is 1/2 correct in nature.
Randall is 1/2 correct in nature and his post was not utter and complete nonsense.
Mike
Nonsense is a BROAD statement. If someone wishes to be precise with the statements then we can lay a claim on real nonsense. My experience is in the NEC and the NEC does not have a problem with either application and since HI’s dont deal in rhelms they should not dabble in I would prefer to tell the HI’s to walk away from the situation.
Also…don’t envy me…my wife and child are the ones who have suffered from my selfish adventure into the National Electrical Code.
The picture looks to be a two position switch, Middle NO contact, Up current flow from Generator, Down current flow from power company. As Paul stated using a approved transfer switch you do not break grounded conductors.