Generator power up procedure

[bchauvette]

I was reading the instruction label on a 8K Chinese generator. It had numerous beakers. The instructions said to individually turn the breakers on one at a time starting with the highest load. I understand the logic behind this. If the power has been off for a while things like the refrigerator, air conditioning hot water heater etc. will be calling for power with the start up surges happening all at once.

Naturally all this depends on your specific loads and generator size. What are your thoughts? What is your power up procedure?

Also what are your thoughts on using a transfer switch VS. a breaker panel interlock plate.

http://www.ebay.com/itm/like/171653738123

Just about finished installing my MEP003.

 

[FloridaAKM]

That will probably work just fine, but is it up to code as far as the electric company & electrical inspectors? IT looks more of an electrical LOTO device than anything else. The bottom line is the electric company wants no back fed power from an electric generator to energize their lines when they are working what they believe are dead lines. It is a clever idea for someone to market & is much cheaper than a transfer switch! The rest of the guys will be up to chime in shortly!

 

[DieselAddict]

Modern heatpumps/AC units have timers on them to protect the compressors from short cycling due to power blips. You shouldn't have to worry about the AC unit starting up immediately upon power up. The fan may start quickly but the compressor shouldn't. I have a MEP003 for backup at my house and I don't worry about staging on loads. I just flip the switch. My normal background load is under 1kw which is not even noticed by the MEP. About 5 minutes after the generator is up and running the AC will restart if called for.

As far as the interlock/transfer switch decision goes, that has been discussed a number of times. People have strong opinions about that. My thoughts as an electrical engineer and a licensed electrician is that a transfer switch is preferable because there are fewer failure modes that could allow power to be reverse fed onto the local power system. If you can put in a transfer switch I would strongly recommend one.

That said, an interlock is acceptable in most locales. As stated above be sure to check your local codes to make sure it is allowed if you decide to go that way.
Edit - Also make sure you install it correctly and that it can't be easily defeated.

 

[Triple Jim]

My 003A seems to have overload capability to match the surge from turning everything on at once. When I get it running and turn on its breaker, there is a small and momentary sag in engine speed, nothing more.

 

[Isaac-1]

I tend to agree with DieselAddict's post, they are legal in most places, but a real transfer switch is safer, the problem is when you flip a breaker off, you have no way of knowing that in internal connection opened. This means even using an interlock it is possible you are switching both sides to being live at once and have no way of knowing it during an outage. Sure it is rare for this to happen, but it can happen when the contact points weld themselves together. I had it happen to me on a residential lighting circuit at my mother's house just a year or two ago, I needed to replace the light switch as it was getting flaky and no breaker in the panel would shut off the lights. I don't remember the brand of the panel maybe Sq. D, but it would have been installed in about 1980, and who knows when the breaker welded itself closed, it could have been that way for years.

Ike

ps if you do decide to go with an interlock
take a look at http://www.natramelec.com/ also

 

[jimbo913]

Isaac-1, With an interlock you are switching the main power switch off. This is a switch not a breaker - right? It must be pretty reliable or the consumer could get shocked if it failed when in the off position.

I personally think it would be extremely rare for that switch to fail and although I have not seen inside one it might even be impossible to fail in the incorrect position.

 

[bchauvette]

Isaac-1, With an interlock you are switching the main power switch off. This is a switch not a breaker - right? It must be pretty reliable or the consumer could get shocked if it failed when in the off position.

I personally think it would be extremely rare for that switch to fail and although I have not seen inside one it might even be impossible to fail in the incorrect position.

The main switch is in fact The main breaker rated at the panel ampacity. I agree that although possible the beaker could fail and not open it must be constructed pretty fail safe or death could occur.

Again a transfer switch costs up to $400.00 VS. $60.00 for an interlock.

 

[jimbo913]

I just wonder if it is a different kind of breaker. Mine has a huge throw to it.

One issue I have with transfer switches is that many make you select only a few circuits and I like to manage loads and have access to all circuits in my main and sub panels.

 

[jimbo913]

Lineman are trained to assume power is on but homeowners are not so when they turn that main off they expect it to be off. I will have to dig into this more because now I am curious just how that main breaker differs from a standard breaker.

 

[jimbo913]

Ok, so I see that most main branch breakers are warranted for life which means it must be robust. I could not find any information on how it internally disconnects and if it is different than a regular circuit breaker.

I had a quick look and could not find a transfer switch which didn't have some limitations. Is there an inexpensive disconnect switch available that an electrician could install prior to the main breaker which could be used as added safety in conjunction with an interlock kit? That setup should provide 100% protection if used correctly.

like a 200A double-throw safety switch

 

[rhurey]

That would make the new breaker ahead of the panel your service entrance, require neutral and ground be bonded there, and you have to separate them in your main panel.

The labor on that may shoot inexpensive out of the water.

 

[bchauvette]

I've tried to gather all the grounding bonding info from the site. Correct me if I'm wrong. Basically your are supposed to have only one ground. Generator hooked to the house ground through the house system . Running independently the generator must be grounded on its own . I read the reasoning for this. Something about path of least resistance but don't have a good handle on what they are talking about. What is the reasoning for needing to bond at point A instead of point B. it's all hooked together isn't it? When you say bonded you mean the neutral and ground is hooked together right? Bonding the enclosure connecting the metal box to ground in case there is leaking live electricity it will go through he ground wire and not through your heart.

I have an unusual meter hook up along side the meter box thee is a huge exterior breaker box with one three pole breaker. Whats up with that?

Isn't it just a matter of disconnecting the connecting wire from the neutral and ground bus in the house panel enclosure?

 

[Triple Jim]

If your generator has neutral and ground bonded, and your entrance panel does too, you've effectively made one double conductor out of them, and you've lost all the benefits of having a separate ground wire for safety.

 

[Daybreak]

Howdy,
There are lots of ways to make the connection.
The most important is that some disconnect is there.
A transfer switch needs to be the size of your service. They kinda get pricey being you need 200amp transfer switch with 200amp service. A interlock work with your current service panel. If you have a main line (one of the bigger companies) a proper UL rated interlock is available. (main line would be like GE, Square D, Milbank, Siemens, Eaton and a few others) The maker gives it a UL rating with their equipment.

There are also generator break-out panels. They work good, but you get limited to only a select few breaker items.

The main idea is safety for you, or someone else which does not know your system. The interlock itself is fastened in a way that even with your service panel faceplate removed, it remains in place.

A interlock makes it so your main 200amp breaker has to be off for the generator breaker to be turned on. That means the top 2 breakers are for your generator connection. It also means you are only limited to the size of sub-breakers for your feed. In the picture below, I am using a dual 30amp breaker for the generator feed. If you had a larger units you would then have a dual 50amp breaker here. or whatever size you need.

Make your generator connection so anyone can do it safely. Even if they do not know what they are doing, only one feed can be online at a time.

Since your connecting your generator with 4 wires, you will want to remove the copper plate between the common and ground. The service panel is where the common and ground make the connection to the ground rods, so the generator is not a separately derived system.