Switch Rating / Lighting Transformer

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gonec

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I have taken a exam last week and one question stump me and I was wondering if someone could help. The question appeared vague and not enough detail.

The question was: A switch operates a lighting transformer, what is the rating of the switch? The multiply choices for the question were:
1.5, 2, 2.5 or 3.

I look under Switches Art 404 and Transformer Art 450 but I couldn't find ratings of a switch for a lighting transformer.

As I mention the question was vague and I wasn't sure if they are looking for a switch operating a large transformer or a switch operating a small low lighting transformer.

Any help thanks! GoNEC
 
Re: Switch Rating / Lighting Transformer

I just did a word search of the 2002 NEC. The two word phrase "lighting transformer" does not appear anywhere in the code.

The question does not say what it means by the rating of the switch, and it does not give units of measure (i.e., 2.5 amps, 2.5 volts, 2.5 watts, or 2.5 times the rating of something else). Also, it is not accurate to say that a switch "operates" a transformer. When "on," a switch allows a transformer to operate; when "off," the switch isolates the transformer.

I would give the question writer a failing grade.
 
Re: Switch Rating / Lighting Transformer

I adgree it is a poorly written question. This question appeared on the Delaware State Exam last week. After the test a lot of fellows were taking outside about that question and nobody could figure out what they were talking about. I think I'm going to challege the question to Experior who gave the test
 
Re: Switch Rating / Lighting Transformer

If I were faced with selecting an answer to the question there are the thinks that I would consider:
It couldn't be an isolation switch because an isolation switch can carry a load but is not considered a load break switch. The switch doesn't have to have a HP rating as it isn't used to control a motor. So a common switch capable of carrying and interrupting a load would be selected based upon the FLA of the transformer.
 
Re: Switch Rating / Lighting Transformer

If this is exactly how the question was written, it is very weak. The only thing I came up with is, with a lot of assumptions, is 2. Look at 404.14B.2 (inverse of 50%=2x)
 
Re: Switch Rating / Lighting Transformer

Hey volt101 - Intrestingly after the test I read that section also and few other fellows did and they said what you said "2". Unfortanly , during the test I put "1.5" as a quess because I was spending to much time on this one question. Thanks for your insight I apperciate it.
 
Re: Switch Rating / Lighting Transformer

To gonec: I am a instructor at Delaware Technical & Community College, Stanton Campus, and I had two of my students take that exam, and they have asked me the same question about the switch for the transformer. I do not have a clue.
If you find out, would you please contact me.
 
Re: Switch Rating / Lighting Transformer

Originally posted by volt101:
with a lot of assumptions
Click to expand...
If I remember correctly, the instructions page states "make No assumptions" or "do Not assume anything"

GoNeC, what type of contractor are you? and was this question on the Limited or the Master exam?
 
Re: Switch Rating / Lighting Transformer

Friebel - No problem as soon as I get a chance I'm going to call Experior and ask them on what form I need to challege a question for the DE Master Exam. It should be intresting and I'll share it with you and everybody on the site.
 
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