Absurdly Simple Question II: Transformers

[ronaldrc]

Hey Don

I never thought of that, But I'm retired so it doesn't matter. But all you electricians out their
next time you feed the power to a outside heat pump unit if its next to the main disc. outside
Then according to Dons logic, You can get by without putting a disc. on the heat pump.Just point
to the main service disc. and tell him that is it. It says a disconnect within sight.

I don't think that would fly with my Inspector

 

[LarryFine]

A sheynem dank

Nishto farvos!

Badhkins! :roll:

 

[jwelectric]

Mike,
There is nothing in the rule that says anything about what disconnect that I use to disconnect the transformer. Until the code wording is changed to require an individual disconnect, it will remain my opinion that any disconnect that kills the power to the primary of the transformer meets the rule.

For what it is worth, I think they wanted an individual disconnect, but you can't enforce what they wanted...you can only enforce what they wrote.

How does the feeder disconnect not disconnect the transformer???

This is very simple.

​

450.14 Disconnecting Means.​

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​

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Transformers, other than Class 2 or Class 3 transformers, shall have a disconnecting means located either in sight of the transformer or in a remote location. Where located in a remote location, the disconnecting means shall be lockable, and the location shall be field marked on the transformer.
​

It doesn't say "feeders" must have a disconnect it clearly says that the disconnect is for the transformer.

Yes you are reading it the way you want it to be read and I am reading it the way the intent is meant. I suppose it is likened to the strap being inside the box when there is no verbage requireing any thing to be in the box. I suppose we read anything in a manner that suits our arguement.
​

 

[kwired]

I don?t think that in over 40 years of electrical work I have ever seen a panelboard that couldn?t be turned off. Maybe I have missed something through the years.
But to compare a panelboard to a transformer????????????
I thought we were discussing transformers not panelboards.

The proposal for the change has even stated that the new requirement would bring transformers to the same requirements as motors, appliances, etc. so we are discussing transformers as well as other items that may or may not have similar requirement as was mentioned.

A feeder is supplying transformers on each of a three floor building. Something goes wrong with the second floor transformer and now all three floors are shut down.
If this can not be seen as a safety issue then so be it but there were enough to see it as one that action was taken. Now supply a disconnect for each transformer and make it either insight of or lockable.

The same can be said by replacing the word transformer with panelboard:

A feeder is supplying panelboards on each of a three floor building. Something goes wrong with the second floor panelboard and now all three floors are shut down.
If this can not be seen as a safety issue then so be it but there were enough to see it as one that action was taken. Now supply a disconnect for each panelboard and make it either insight of or lockable.

Why does that make panelboards and transformers different when it comes to the debate in this post

For an appliance such as a water heater or cooking equipment the codes requires a means to lockout the circuit that supplies these appliances when the disconnect is not within sight.
Is by some means other than my poor brain is capable of understanding that makes the circuit supplying a transformer less likely to be inadvertently energized? Well the TCC did not think so as this action was taken due to their study. It was totally outside the purpose as outlined in 90.1

Bob and Don

If there is a feeder that is supplying more than one transformer the disconnect for the feeders would not be the disconnect required by the new 450.14.

The new 450.14 is directed to transformers not the overcurrent device for the feeders as outlined in 215.3. There is no mention of feeders in this new section but it clearly states transformers will be having a disconnect.

Bob please explain what you are talking about with panels. I thought this discussion was about transformers. Are we reaching for straws here or some other tactic of distraction?

I see no distraction just comparison to try justify the reason for the 450.14 change.

Hey Don

I never thought of that, But I'm retired so it doesn't matter. But all you electricians out their
next time you feed the power to a outside heat pump unit if its next to the main disc. outside
Then according to Dons logic, You can get by without putting a disc. on the heat pump.Just point
to the main service disc. and tell him that is it. It says a disconnect within sight.

I don't think that would fly with my Inspector

This is very simple.


450.14 Disconnecting Means.

​

​

Transformers, other than Class 2 or Class 3 transformers, shall have a disconnecting means located either in sight of the transformer or in a remote location. Where located in a remote location, the disconnecting means shall be lockable, and the location shall be field marked on the transformer.​

It doesn't say "feeders" must have a disconnect it clearly says that the disconnect is for the transformer.​

Yes you are reading it the way you want it to be read and I am reading it the way the intent is meant. I suppose it is likened to the strap being inside the box when there is no verbage requireing any thing to be in the box. I suppose we read anything in a manner that suits our arguement. ​

read your quote of 450.14 again and tell us where the word individual is located.​

and how do you know you are reading it the way the intent is meant? maybe we all are wrong on the intent, the words are what they are, the intent is only substantiation for printing the words in the final copy, and sometimes they find they still need to change the words the next cycle because it can be interpreted in a way they did not think of.​

References to other sections that we are supposably trying to be in line with:​

422.30 General.
A means shall be provided to disconnect each appliance from all ungrounded conductors in accordance with the following sections of Part III. If an appliance is supplied by more than one source, the disconnecting means shall be grouped and identified.​

430.102 Location.
(A) Controller. An individual disconnecting means shall be provided for each controller and shall disconnect the controller. The disconnecting means shall be located in sight from the controller location.​

...​

(B) Motor. A disconnecting means shall be provided for a motor in accordance with (B)(1) or (B)(2).
(1) Separate Motor Disconnect. A disconnecting means for the motor shall be located in sight from the motor location and the driven machinery location.
(2) Controller Disconnect. The controller disconnecting means required in accordance with 430.102(A) shall be permitted to serve as the disconnecting means for the motor if it is in sight from the motor location and the driven machinery location.​

440.11 General.
The provisions of Part II are intended to require disconnecting means capable of disconnecting air-conditioning and refrigerating equipment, including motor-compressors and controllers from the circuit conductors.​

This one does not require an individual disconnect for each piece of equipment, however it is common practice to do so and many probably think it is required.​

 

[defears]

The problem with the wording is, OR in a remote location. Now if I look in the dictionary I see that it means the local disco is OPTIONAL.

So the only change is the label and a permanant lockout on the breaker feeding it.

 

[George Stolz]

Another example of the concept would be 422.34, where it mentions the service disconnecting means as being the other disconnecting means for complying with the primary requirement of 422.34.

 

[don_resqcapt19]

...

So the only change is the label and a permanant lockout on the breaker feeding it.

This rule doesn't even require the permanent means of lockout on the breaker.

 

[don_resqcapt19]

This is very simple.

Yes it is very simple

...

It doesn't say "feeders" must have a disconnect it clearly says that the disconnect is for the transformer.

I ask again "how does the feeder disconnect not disconnect the transformer"?

Yes you are reading it the way you want it to be read and I am reading it the way the intent is meant.

Intent is not enforceable, only the actual code rule is enforceable. There are plenty of examples in the code where the wording makes it clear that the rule requires an individual means of disconnect. This rule is not one of them, therefore the rule does not require an individual means of disconnect. If the rule is to permit safe de-energized work on the transformer, any disconnect that kills the primary side will serve the purpose.

... I suppose we read anything in a manner that suits our argument.

I try to read the words as written as that is the only thing that can be enforced.
​

 

[don_resqcapt19]

Hey Don

I never thought of that, But I'm retired so it doesn't matter. But all you electricians out their
next time you feed the power to a outside heat pump unit if its next to the main disc. outside
Then according to Dons logic, You can get by without putting a disc. on the heat pump.Just point
to the main service disc. and tell him that is it. It says a disconnect within sight.

I don't think that would fly with my Inspector

Assuming that the service disconnect is within sight of the heat pump and they you have provided the required overcurrent protection the main service disconnect meets the rule. Just like with the transformers, it is very unlikely that a service or feeder disconnect can provide that protection. The biggest difference in the heat pump disconnect rule and the transformer disconnect rule is that the disconnect for the heat pump must be within sight from the heat pump and the one for the transformer is permitted to be at a remote location.

 

[defears]

Well, I'll feel warm and fuzzy putting the $10 breaker lock on vs. $800 disco. I'm all for safety, and both accomplish the same thing.

Honestly, at this point I'm surprised the manufacturers don't put breaker locks built in to all breakers and primary and secondary discos built in to the tranformers. I know they make them, but make them standard. Since they pretty much are the CMP, why not go all out crazy-safety.

 

[George Stolz]

Who would take that plunge first? If my competitor just eliminated a cheaper line of products, you can bet your boots I'll hold back and be the lowest price and sell a lot of product.

 

[mivey]

I read it...Did You?

Don't forget the in part part:

...
Add new text to read as follows: ... By installing a disconnecting means within sight of the transformer, maintenance and modification of the primary and/or secondary side of the transformer would be safer for the electricians working on the transformer...
...
... CMP-9 rejects the requirement that this disconnecting means must be located within sight of the transformer.

Ditto this:

The rule really doesn't require anything new, other than the label telling you where the remote disconnect is located.

 

[mivey]

...there are preventive maintenance work and inspections required by lenders on service equipment, XFMR's and so on at a regular basis. They check torques and other area as well as cleaning out portions of the equipment on an annual basis..

And if they don't want a larger area outage, then they should put in some local disconnects as part of the design that includes digging around in the transformers on a regular basis.

FWIW, I am currently working on a proposal that will require safety switches for safety switches.

I thought about photo-shopping an infinity mirror with disconnects but am feeling too lazy.

 

[barclayd]

Is there anything preventing the use of a Plug & Receptacle as a disconnect? They make some REALLY BIG Plugs & Receptacles. You gotta use two hands on some of them Plugs.
db

 

[don_resqcapt19]

Is there anything preventing the use of a Plug & Receptacle as a disconnect? They make some REALLY BIG Plugs & Receptacles. You gotta use two hands on some of them Plugs.
db

Nothing other than cost. A big plug and receptacle would cost a lot more than a disconnect.

 

[iwire]

I will go with 400.8(1) on that one.

 

[barclayd]

I will go with 400.8(1) on that one.

No cord - Sealtite.
db

 

[barclayd]

Nothing other than cost. A big plug and receptacle would cost a lot more than a disconnect.

So now, after 10 pages of responses, you want to introduce common sense?
db

 

[iwire]

So now, after 10 pages of responses, you want to introduce common sense?
db

:grin::grin:

He is nuts like that.

 

[pfalcon]

an absurdly simple question from you scares me more than a snake:grin:
both may bite you....
...
come on snake...

The rule really doesn't require anything new, other than the label telling you where the remote disconnect is located.

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?