Absurdly Simple Question II: Transformers

[mivey]

An interesting point with which I have to agree.

Though looking at 430.102(B)(2) gives me some pause in all this. The implication here is that upstream disconnects do not qualify as motor disconnects unless called out. Therefore upstream disconnects should not qualify as transformer disconnects unless called out.

Out of curiousity, why would you install a disconnect that was not lockable?

Another believer joins the fold. Welcome, O wise one.

 

[pete m.]

I'm in Don's camp on this.

I have an issue with the marking required on the transformer denoting where the disconnecting means is located. How would one mark this? What if it read something like: "Transformer disconnect located in room 123"

The issue is that unless the room numbers are on the door to the room or located on a wall near the door an electrician unfamiliar with the building would have to search for the disconnect the same as he/she would without the label even being placed on the transformer. And, if by chance, a copy of the original construction documents were available that showed the room locations that same set of drawings probably has a one-line that a qualified individual could read and determine where the disconnecting means is located.

So after all that I suppose I don't really even see the need for the label to be applied (short of the fact that it's required)

Pete

 

[mivey]

I have an issue with the marking required on the transformer denoting where the disconnecting means is located. How would one mark this? What if it read something like: "Transformer disconnect located in room 123"

It does not give directions or a map to the location, but that is not required. I guess it just helps narrow the search.

 

[pete m.]

It does not give directions or a map to the location, but that is not required. I guess it just helps narrow the search.

I believe that the intent was to eliminate the search entirely. I just don't know how the label would be worded to accomplish this. So, unless one could come up with that method I believe we are right back to relying on the qualified individual.

Secondly, IMHO if there is a qualified individual then this new code is useless. (sorry I'm getting dangerously close to a rant:grin

Pete

 

[don_resqcapt19]

...
Out of curiousity, why would you install a disconnect that was not lockable?

A standard breaker without an accessory device is not "lockable" per the disconnect rules found in some other code sections that use the following wording.

The provision for locking or adding a lock to the controller disconnecting means shall be installed on or at the switch or circuit breaker used as the disconnecting means and shall remain in place with or without the lock installed.

The new transformer disconnect rule does not use this language, so it would be my opinion that any standard breaker can be used as the required transformer disconnect. There are a lot of external temporary devices that can be used for this purpose.

 

[mivey]

I believe that the intent was to eliminate the search entirely. I just don't know how the label would be worded to accomplish this. So, unless one could come up with that method I believe we are right back to relying on the qualified individual.

Secondly, IMHO if there is a qualified individual then this new code is useless. (sorry I'm getting dangerously close to a rant:grin

Pete

I don't see how one could ever get around using qualified people. But I see your point in that the label could be practically useless.

I never fully trust what is labeled, especially where my safety is concerned. The newer or older the label, the less I trust it.

I guess the label makes the insurance companies feel better. And it brings you a warm fuzzy feeling when the label is actually helpful and correct.

 

[pete m.]

I never fully trust what is labeled, especially where my safety is concerned. The newer or older the label, the less I trust it.

I'm with you 100% on that!!

Pete

 

[kwired]

I don't see how one could ever get around using qualified people. But I see your point in that the label could be practically useless.

I never fully trust what is labeled, especially where my safety is concerned. The newer or older the label, the less I trust it.

I guess the label makes the insurance companies feel better. And it brings you a warm fuzzy feeling when the label is actually helpful and correct.

Do you trust your own labels when working on something you installed?

Even if you trust the labels good work practices involve disconnection, LOTO, and test for voltage before proceeding with other work. Even if disconnect is right next to equipment and is obvious what it serves. Seen safety switches fail before and they sometimes don't open all poles when things go bad.

 

[pete m.]

Do you trust your own labels when working on something you installed?

Even if you trust the labels good work practices involve disconnection, LOTO, and test for voltage before proceeding with other work. Even if disconnect is right next to equipment and is obvious what it serves. Seen safety switches fail before and they sometimes don't open all poles when things go bad.

Your sounding just like a qualified person:grin:

Even though there is a "label" because of your experience and common sense you know better than to trust ANY labeling.

Pete

 

[Twoskinsoneman]

Just to put my two cents in. I think labeling is great. Even though I don't really think it is a safety issue and therefore not really a code issue, I think it makes it a lot easier if the disconnect location is identified at the piece of equipment I'm working on. Especially in a building with electrical rooms located on multiple floors. Just saves a little time.
Not a safety issue because if you work it live because you couldn't find the disconnect quickly you shouldn't be working it anyway.

 

[mivey]

Do you trust your own labels when working on something you installed?

After verification, and only if I know I'm the only one involved.

Even if you trust the labels good work practices involve disconnection, LOTO, and test for voltage before proceeding with other work. Even if disconnect is right next to equipment and is obvious what it serves. Seen safety switches fail before and they sometimes don't open all poles when things go bad.

That's correct. But it is a simple fact that I am a lot more cautious when other people are involved. To err on the side of caution, I probably should treat my own work the same way but I don't.

 

[mivey]

Just to put my two cents in. I think labeling is great. Even though I don't really think it is a safety issue and therefore not really a code issue, I think it makes it a lot easier if the disconnect location is identified at the piece of equipment I'm working on. Especially in a building with electrical rooms located on multiple floors. Just saves a little time.
Not a safety issue because if you work it live because you couldn't find the disconnect quickly you shouldn't be working it anyway.

You should always treat it live whenever you can. You never know if some knuckle-head double-fed or crossed circuits and then some genius goes and starts flipping breakers after you locked your's out. Even if I have checked a box as dead with my meter, I have a habit of grounding a wire if there is some reason I need to bare-hand it.