Exam questions that I remember

[cobrahead]

I just went and took a master exam today. I am trying to remember some of the questions that I was unclear on, but I cannot remember them verbatim. A couple that stick out right now are as follows:

1) How much dedicated electrical space (I think that was the phrase) must exist above a 1200A rated service switch operating under 600V. Is this 6' ?

2) Power conversion as it relates to adjustable speed motors (or drives, can't remember the exact wording) is referring to/concerning 1) harmonics 2) amps 3) frequency 4) voltage. I think it is voltage or frequency, but I cannot narrow it down.

3) What is the rating of a pre-wired modular surface mounted raceway? 1) 600V 15A 2) 600V 20A 3) 300V 15A 4) 300V 20A

4) In what case does a receptacle in a closet not require AFCI protection? I don't remember all the possible answers but there were two about fire alarms and one about a security alarm panel

5) What is the maximum length of a unprotected (indoor) feeder tap? I chose 10'

I wish I could remember these more clearly, but my head is still whirling from the 103 questions in 5 hours. I got a 72, close but no cigar... :slaphead:

 

[Dennis Alwon]

#1-- I would say 6' based on 110.26(I)(a)

 

[Dennis Alwon]

#4-- reference 760.41(B) Non Power limited fire alarm circuits

(B) Branch Circuit. The branch circuit supplying the fire alarm equipment(s) shall supply no other loads. The location of the branch-circuit overcurrent protective device shall be permanently identified at the fire alarm control unit. The circuit disconnecting means shall have red identification, shall be accessible only to qualified personnel, and shall be identified as ?FIRE ALARM CIRCUIT.? The red identification shall not damage the overcurrent protective devices or obscure the manufacturer?s markings. This branch circuit shall not be supplied through ground-fault
circuit interrupters or arc-fault circuit-interrupters.

 

[Dennis Alwon]

I agree with the 10' on the tap conductors indoor

The surface raceway is in 604.6(A)(5)

(5) Raceway. Prewired, modular, surface-mounted raceways shall be listed for the use, rated nominal 600 volts, 20 amperes,
and installed in accordance with 386.12, 386.30, 386.60, and 386.100.

 

[Dennis Alwon]

When I see adjustable speed drive I am assuming variable frequency drive but I am not certain on that.

 

[GoldDigger]

4) In what case does a receptacle in a closet not require AFCI protection? I don't remember all the possible answers but there were two about fire alarms and one about a security alarm panel

This is a tricky one where the exact wording may be important.
If an AFCI is required in the closet for general receptacle and lighting outlets, (120/240V, 15 or 20A), then a provision that a fire alarm branch circuit must not be on an AFCI could be just as easily be interpreted as prohibiting the fire panel from attaching to receptacle in the closet as allowing the receptacle in the closet to be non-AFCI.

A receptacle in a closet might not need AFCI if the closet is located off a room which does not require AFCI protection. The code cycle applicable for your exam matters here.

Depending on the wording, it could either be a difficult question or a bad question.

 

[cobrahead]

Thanks! If I remember any more questions that hung me up I will post them. Sometimes they come back to me while I am studying.

 

[ggunn]

Thanks! If I remember any more questions that hung me up I will post them. Sometimes they come back to me while I am studying.

One thing that I remember from my NABCEP (solar) exam is that for any question any choice that involves a painted wooden ladder can be eliminated immediately.

It was a sucker question and I fell for it.

 

[petersonra]

I just went and took a master exam today. I am trying to remember some of the questions that I was unclear on, but I cannot remember them verbatim. A couple that stick out right now are as follows:

1) How much dedicated electrical space (I think that was the phrase) must exist above a 1200A rated service switch operating under 600V. Is this 6' ?

I think you have it.

2) Power conversion as it relates to adjustable speed motors (or drives, can't remember the exact wording) is referring to/concerning 1) harmonics 2) amps 3) frequency 4) voltage. I think it is voltage or frequency, but I cannot narrow it down.

They typically control both frequency and voltage.

3) What is the rating of a pre-wired modular surface mounted raceway? 1) 600V 15A 2) 600V 20A 3) 300V 15A 4) 300V 20A

I vote for 3 or 4, but don't know with any certainty.

4) In what case does a receptacle in a closet not require AFCI protection? I don't remember all the possible answers but there were two about fire alarms and one about a security alarm panel

No idea.

5) What is the maximum length of a unprotected (indoor) feeder tap? I chose 10'

100 ft IMO.

I wish I could remember these more clearly, but my head is still whirling from the 103 questions in 5 hours. I got a 72, close but no cigar... :slaphead:

Some interesting questions.

 

[MichaelKelley]

Good, that you are sharing the question here, which may some idea about the question, but it will not be same for everyone as there will be a lot of question and you will get randomly.

 

[cobrahead]

Good, that you are sharing the question here, which may some idea about the question, but it will not be same for everyone as there will be a lot of question and you will get randomly.

Yeah, I have taken the exam more than once now :dunce: and while the questions are randomly pulled from a pool I have started to see some of them multiple times.

 

[kwired]

For the feeder tap question look at 240.21(B).

There is a 10 foot tap rule and two different 25 foot tap rules - each with their own set of conditions. There is also an unlimited length for outdoor feeder taps.

There is a rule for taps over 25 feet long - but does have pretty limited applications, the answer to the question is in this rule and is 100 feet, but is only allowed to be 25 feet horizontally and the rest must be vertical in a high bay application.

 

[cobrahead]

For the feeder tap question look at 240.21(B).

There is a 10 foot tap rule and two different 25 foot tap rules - each with their own set of conditions. There is also an unlimited length for outdoor feeder taps.

There is a rule for taps over 25 feet long - but does have pretty limited applications, the answer to the question is in this rule and is 100 feet, but is only allowed to be 25 feet horizontally and the rest must be vertical in a high bay application.

The only thing that is hanging me up on this question is the 'not protected' portion. 240.21(B)(1) is the only tap length that does not include the wording 'The tap conductors are protected from physical damage by being enclosed in an approved raceway or by other approved means.'

 

[kwired]

The only thing that is hanging me up on this question is the 'not protected' portion. 240.21(B)(1) is the only tap length that does not include the wording 'The tap conductors are protected from physical damage by being enclosed in an approved raceway or by other approved means.'

I agree the "not protected" wording is possibly poorly worded and adds confusion. That said conductors covered by 240.21(B)(1) must be in a raceway according to subpart (3) which to me means the raceway provides physical protection, and it does not give you the option of "other approved means".

 

[cobrahead]

I agree the "not protected" wording is possibly poorly worded and adds confusion. That said conductors covered by 240.21(B)(1) must be in a raceway according to subpart (3) which to me means the raceway provides physical protection, and it does not give you the option of "other approved means".

I agree that this is a poorly worded question. The question specifically said 'indoor'



(2) The tap conductors do not extend beyond the switchboard,
panelboard, disconnecting means, or control devices
they supply. OK

(3) Except at the point of connection to the feeder, the tap
conductors are enclosed in a raceway, which shall extend
from the tap to the enclosure of an enclosed
switchboard, panelboard, or control devices, or to the
back of an open switchboard. OK

BUT...

(4) For field installations, if the tap conductors leave the
enclosure or vault in which the tap is made, the ampacity
of the tap conductors is not less than one-tenth of
the rating of the overcurrent device protecting the
feeder conductors. !@#?!?!?

 

[kwired]

BUT...

(4) For field installations, if the tap conductors leave the
enclosure or vault in which the tap is made, the ampacity
of the tap conductors is not less than one-tenth of
the rating of the overcurrent device protecting the
feeder conductors. !@#?!?!?

This means if the tap conductors do not leave the enclosure they tap to the feeder in there is no minimum size tap conductor, if they do leave the enclosure they must be at least one tenth the ampacity of the feeder overcurrent device. So if the feeder were 400 amps and the tap conductor left the enclosure then it must be at least a 40 amp conductor.

EDIT: I said no minimum, but it still must at least be the ampacity of the load supplied by the tap.

 

[cobrahead]

I agree with the 10' on the tap conductors indoor

The surface raceway is in 604.6(A)(5)

Kwired is saying the answer is (in his interpretation) is 25' ... and he makes a good case. What do you think? There is a good chance I will see this one again, so I want to nail it down if possible. Thanks for the help!:thumbsup:

 

[Gregg Harris]

Kwired is saying the answer is (in his interpretation) is 25' ... and he makes a good case. What do you think? There is a good chance I will see this one again, so I want to nail it down if possible. Thanks for the help!:thumbsup:

I am going with 100 feet;
All four choices are protected by raceway, and all four are permitted without over current protection.

(4) Taps over 7.5 m (25 ft) Long. Where the feeder is in a high bay manufacturing building over 11 m (35 ft) high at walls and the installation complies with all the following conditions: (1)

Conditions of maintenance and supervision ensure that only qualified persons service the systems.


(2)

The tap conductors are not over 7.5 m (25 ft) long horizontally and not over 30 m (100 ft) total length.

 

[cobrahead]

I am going with 100 feet;
All four choices are protected by raceway, and all four are permitted without over current protection.

(4) Taps over 7.5 m (25 ft) Long. Where the feeder is in a high bay manufacturing building over 11 m (35 ft) high at walls and the installation complies with all the following conditions: (1)

Conditions of maintenance and supervision ensure that only qualified persons service the systems.


(2)

The tap conductors are not over 7.5 m (25 ft) long horizontally and not over 30 m (100 ft) total length.

Heh. Now I have people telling me it is either 10', 25' or 100' ... and they all make good points! I am leaning towards the 100' unless someone else can convince me otherwise. I said 10' on the test last time.

 

[kwired]

Heh. Now I have people telling me it is either 10', 25' or 100' ... and they all make good points! I am leaning towards the 100' unless someone else can convince me otherwise. I said 10' on the test last time.

The answer to your question is 100 feet. But you will run into the 10' and 25' limitations much more often, unless maybe all you ever work in is high bay manufacturing facilities. I don't like the selection of the question, and would much rather they gave more of an application to apply instead of such a vague question. Only application they gave was that it is indoors. You ask us a similar question here on the forum and first thing most will be responding with is wanting to know more specifics of the application.