Disconnecting a standby generator

[gball]

Starting the ground work for my 24'x30' attached garage this week. i am also redoing the perimeter drains and re-sealing the walls. i need to move my Guardian standby generator to dig up the house foundation where it sits. Removing the LP supply line is simple, but what needs to be done to Safely disconnect from the house power/breaker box? actually, only need to disconnect generator from the "External connection box". i know my way around electrical and have some line testers but never messed with a built in generator. this is a "Generac Guardian model 04390-2 automatic standby generator". Thanks.

 

[pattenp]

Nothing special needs to be done. Disconnect the cable at the gen or the box. Obviously without the gen running. OH... disconnect the battery first at the gen to be safe.

 

[MBfreak]

Hi.
Not having any knowledge on US safety rules, I nevertheless would like to suggest the following before working on the "far end " of a power cable.

1 Disconnect at source.
This can be done in different ways. Some rules ( even laws) may require that you establish a visible disconnection point where there is no insulation material between the incoming and outgoing part that is not grounded in the middle.
2 Mark/lock out the disconnection point.
Padlocked , removed breaker, removed fuses, disconnected cable etc.
3Verify zero voltage
Do this at both ends with a real tester that allows you to probe the connections with a decent flash over protection. Also verify that the feeding point IS LIVE, otherwise the zero voltage check is dubious.
4 Short/Ground ( optional)
Short each disconnected phase to ground at the disconection point with a fault current rated grounding device.

5 NOW YOU CAN work on the genset.
Remove its starter battery , do a NEW zero voltage check again and then physically disconnect. Bundle the disconnected ends together and to ground with a fault current rated connection. Weatherproof the cable sealing end.


Exaggerated?
No, not at all. I have had the misfortune of having two guys on my work crews electrocuted over the years. Both were due to negligence and sloppy work permit procedures.
Horrible.

Ola

 

[theoldwizard1]

... disconnect the battery first at the gen to be safe.

ABSOLUTELY !

You don't want something you are doing to trigger the automatic startup !

 

[wyliesdiesels]

Make sure transfer switch or generator back-fed breaker is off and locked/tagged out! Check the terminals in the junction box, with a voltage tester, to make sure the power is off! Obviously, make sure generator is in off position and disconnect starter battery! Mark, w/ colored electrical tape if leads are not color coded, and disconnect leads from transfer switch/junction box. It might be easier to move the generator w/ the cable whip removed (so u don't have to deal with it dragging on the ground), so u could remove the cable whip from the generator as well.

 

[VHF]

If you have an ATS (automatic transfer swithch) for your generator, you need to remove the small fuses inside the ATS enclosure. Two of them provide 240VAC on the N1/N2 control wires to the generator; one of them powers the battery charges (on some models of Gaurdian/Generac generators.)

Before doing this make sure (a.) generator is switched to off and (b.) turn off breaker feeding the ATS. Once you've removed the fuses and put the cover back on the ATS you can turn on the breaker feeding the ATS to restore power to the circuits on the ATS.

Once the battery is disconnected, it will then be safe to break conections at the outside junction box as there will be no voltage present on any of the wires.

 

[madosta]

I have seen some generators fed with a 120v live circuit from the building to the generator for battery maintainers.

No idea if yours is wired with something like this, but you might just want to check for hot wires in the generator.

 

[Thruxton]

You need to RTFM asap, before you touch a thing inside that transfer switch!! You are dealing with TWO live circuits on a Guardian, and they BOTH need to be off for any kind of maintenance.

 

[gball]

Thuxton, what does RTFM mean? and VHf, your comment cleared up some of my uncertainty. turning off the breakers feeding out to the gen. shuts down all the circuits that are run by the gen. so power will be restored to them after i disconnect and turn back on the feeding breakers?


oh, if Rtfm is referring to the manual...yea, i read it...thanks for the help.... shows all about installing the system, little about maintaining and NOTHING about temporally disconnecting.

 

[Thruxton]

Thuxton, what does RTFM mean? and VHf, your comment cleared up some of my uncertainty. turning off the breakers feeding out to the gen. shuts down all the circuits that are run by the gen. so power will be restored to them after i disconnect and turn back on the feeding breakers?


oh, if Rtfm is referring to the manual...yea, i read it...thanks for the help.... shows all about installing the system, little about maintaining and NOTHING about temporally disconnecting.

Didn't mean to be obscure! That is indeed what it means. Look at it this way: you have two sources of power, the grid and the generator itself. On the exterior of my transfer switch it says: "Warning - more than one live circuit." Turning off the main panel breaker turns off power from the grid, but you also have to make absolutely sure the generator is turned off, which the manual should explain. You don't want that thing starting up while you are working on it, obviously. Since I don't know what model you have, I suggested referring to the manual. I hope this is more helpful, and I'll be glad to try to answer any other questions about this you have, although I am no pro.