Transformer above suspended ceiling

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pete25

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I have a 45kVA transformer installed above a suspended ceiling and I would like to know if code allows for the secondary disconnect to also be installed above the suspended ceiling next to the transformer?



Thanks
 
The code does not require that the transformer secondary have a disconnect, but Article 240 will require, in most cases, that the secondary conductors have overcurrent protection. 240.24(A) requires that this overcurrent protection be at a readily accessible location and not more than 6'7" above the floor.
 
don_resqcapt19 said:
The code does not require that the transformer secondary have a disconnect, but Article 240 will require, in most cases, that the secondary conductors have overcurrent protection. 240.24(A) requires that this overcurrent protection be at a readily accessible location and not more than 6'7" above the floor.
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This transformer is above the ceiling grid.

If the equipment protected [in this case a transformer] is not accessible from the floor, the OCPD and/or disconnect does not have to be accessible from the floor or within 6'7" of the floor. . 240.24(A) allows access from a working platform and 240.24(A)(4) allows access by "portable means" for an adjacent install.
 
dcspector said:
David I disagree. The secondary ocpd does not supply the equipment per 240.24(A)(4)
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Agreed, The overcurrent device on the secondary of the transformer is not what 240.24(A)(4) is dealing with. 240.24(A)(4) permits an overcurrent device, say for a motor, to be located above 6'7" if it is located adjacent to the utilization equipment.

Chris
 
If the transformer is feeding a nearby panelboard, a main breaker in the panel will provide secondary OC protection.

Above the ceiling is a good place to get the transformer out of the way.

RC
 
dcspector said:
David I disagree. The secondary ocpd does not supply the equipment per 240.24(A)(4)
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I know that 240.24(A)(4) uses the words "equipment" and "supply" but the transformer is allowed above the ceiling [450.13] and the OCPD is for the transformer secondary and its conductors. . Where the next piece of equipment is doesn't matter for transformer secondary OCPD. . I don't think your interpretation is the right one.

Notice that 240.21 says, "Overcurrent protection shall be provided in each ungrounded circuit conductor and shall be located at the point where the conductors receive their supply except ...." then it goes into taps. . OCPD on the secondary means you don't have a tap. . The OCPD is protecting the conductors at their supply end which is above the ceiling grid which is above 6'7".

raider1 said:
Agreed, The overcurrent device on the secondary of the transformer is not what 240.24(A)(4) is dealing with. 240.24(A)(4) permits an overcurrent device, say for a motor, to be located above 6'7" if it is located adjacent to the utilization equipment.

Chris
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240.24(A)(4) is not restricted to motors or to any other category of load.

iwire said:
I agree not allowed by code (the disconnect location) but commonly done non the less.
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And if commonly passed on plan review and inspection that means there's a whole lot of electricians, reviewers, and inspectors that are either passing it over or don't agree with your interpretation that it's wrong.
 
Ragin Cajun said:
If the transformer is feeding a nearby panelboard, a main breaker in the panel will provide secondary OC protection.

Above the ceiling is a good place to get the transformer out of the way.

RC
Click to expand...

Are you talking about 240.21(C) ?
There's some "hoops" to jump thru if you want that distance to be up to 10' [24.12(C)(2)] or if you want that distance to be up to 25' [24.12(C)(6)]
 
dnem said:
240.24(A)(4) is not restricted to motors or to any other category of load.
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Here is the definition on utilization equipment from Article 100.

"Utilization Equipment. Equipment that utilizes electric energy for electronic, electromechanical, chemical, heating, lighting, or similar purposes."

An overcurrent device installed to protect the secondary conductors of a transformer would not be located "adjacent to utilization equipment", therefore 240.24(A)(4) would not apply.

Here is what 240.24(A)(4) says:

"(4) For overcurrent devices adjacent to utilization equipment that they supply, access shall be permitted to be by portable means."

Chris
 
dnem said:
I know that 240.24(A)(4) uses the words "equipment" and "supply" .
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David bottom line, it says what it says and this disconnect is not on the supply side of the transformer. I agree with Chris.

This is a subject that I have really considered putting in a proposal about.
 
dnem said:
240.24(A)(4) is not restricted to motors or to any other category of load.
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240.24(A)(4) specifies: "For overcurrent devices adjacent to utilization equipment that they supply, access shall be permitted to be by portable means.

Article 100 defines utilization equipment as: Utilization Equipment. Equipment that utilizes electric energy for electronic, electromechanical, chemical, heating, lighting, or similar purposes.

I don't believe that a transformer or the conductors from the secondary side meet that definition. That being said, IMHO, 240.24(A)(4) could not be utilized for the disconnect on the secondary side of the transformer.

We don't know from the OP if this transformer is a WYE or DELTA system. If it is a DELTA system 240.21(C) would allow the primary OCPD to be utilized to protect the secondary conductors making this whole thread an exercise in futility.

Pete
 
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