Generator disconnect
- Thread starter Danielt
- Start date
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- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Same as any ocpd being locked open, for worker safety
mopowr steve
Senior Member
- Location
- NW Ohio
- Occupation
- Electrical contractor
I think that the breaker qualifies that is under the generator cover, cause those covers are lockable.
- Location
- Illinois
- Occupation
- retired electrician
A lockable cover does not equal a lockable breaker.
But if the disconnect is on the conductors going to the transfer switch, they aren't energized unless the generator is running, so why disconnect them while servicing?
If you're servicing the generator and need to run it, you turn off the internal breaker. Or even if you don't, you're just energizing the wires to the transfer switch, where they'll stop.
The only energized conductors in the generator are the control/monitoring wires, which are usually line voltage. These are the only ones that seem to need a disconnect, but that's not what 445.18 seems to be saying
If you're servicing the generator and need to run it, you turn off the internal breaker. Or even if you don't, you're just energizing the wires to the transfer switch, where they'll stop.
The only energized conductors in the generator are the control/monitoring wires, which are usually line voltage. These are the only ones that seem to need a disconnect, but that's not what 445.18 seems to be saying
mopowr steve
Senior Member
- Location
- NW Ohio
- Occupation
- Electrical contractor
Is this what it says a “lockable breaker” or a “lockable disconnect” if the latter, any means of disconnect under a lockable cover should qualify
- Location
- Illinois
- Occupation
- retired electrician
A lock on a cover never equals a locked device...a disconnect lock must lock the breaker or switch operating handle.
mopowr steve
Senior Member
- Location
- NW Ohio
- Occupation
- Electrical contractor
It should when a device is behind that lockable cover.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Are you talking about a disconnect at a building for a generator that is located remotely from the building?
If so, that's no different from a disconnect for any separate structure. The genny is a remote power source.
I haven't installed a disconnect at a generator, but I've used a non-fused AC disconnect on a house wall.
If so, that's no different from a disconnect for any separate structure. The genny is a remote power source.
I haven't installed a disconnect at a generator, but I've used a non-fused AC disconnect on a house wall.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
I designed a panelboard cover lock that OSHA liked, you turned off the breakers you wanted, the bar prevented the cover from being opened, and a lock and key that only the person that installed it has. Where it is not legal, is using the factory cover lock that uses a common key.
- Location
- Illinois
- Occupation
- retired electrician
Sorry...it doesn't
- Location
- Illinois
- Occupation
- retired electrician
Do you have any official document from OSHA that says that is an acceptable lockout?
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Then that would apply to a panel board cover with a lock in the door, the issue is the cover can be removed.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
And everybody and their brother has a factory key. On a side note though, panelboards usually require the door to be open, before the cover screws can be removed. But loadcenters, yes, the cover can be removed.
I'm trying to understand the code reference from the op , and my previous comment. Everyone is hung up on the locking aspect, I'm wondering about the purpose or point of having a disconnect. Does the breaker in the generator fill the need for a disconnect in 445.18?
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
See the second post
mopowr steve
Senior Member
- Location
- NW Ohio
- Occupation
- Electrical contractor
Exactly,
To remove a cover that is locked is a secondary action most likely performed by a individual knowledgeable of possible hazards.
So I guess the question is, does the code specifically say the device needs locked or that a means to lock the disconnect applies?
mopowr steve
Senior Member
- Location
- NW Ohio
- Occupation
- Electrical contractor
We’re debating here about this, because some of us believe that breaker qualifies if satisfied by the language and intent of the code.
- Location
- Illinois
- Occupation
- retired electrician
The code language in 110.25 says the disconnect must be lockable in the open position....the cover is not the disconnect.
Okay.
I believe when the code says lockable, it's a reference to OSHAs lockout/tagout. Neither the generator breaker nor the cover have means of locking it out, of placing a physical lock on it.
Therefore, a disconnect is called for by Code.
If it's on the conductors between the generator and the transfer switch, what is it for? To work on the transfer switch safely?
The only reason I could come up with is a fire situation, and the generator is running, and the fire department can disconnect the generator from the building. But they would fist get to the switchgear/main to disconnect normal power,as they would if the building didn't have a generator.
But then why have it lockable? As I said , that is usually a requirement for servicing equipment.
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