electricista

This is why I do so poorly in test...

manchestersparky

New Question:
Electrical Non-Metallic Tubing ____________ permitted to be run through Electrical Metallic Tubing in spaces used for enviromental air.

A) Is
B) Is Not

2008 Nec code Art. _________________

JohnJ0906

A. Is permitted.
300.22(C)(1)

__________________
John from Baltimore
"One day at a Time"
All responses based on the '08 NEC
It's not my fault, it's not my problem, I'm not your solution.

manchestersparky

where's your question?
Lets see if we can get this thread going

electricista

Okay here is an easy one. What is the smallest size copper grounded conductor allowed by the NEC for a 200 amp service?

Greg

Disclaimer: This is my weakness. I'm better with motors.

If the service is a resi, I say a #1.

Based off of T. 310.15(B)(6), Art. 310.15(B)(6) & Art. 220.61 2005 NEC

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Greg

New Question

_________ A protective device for assembly as an integral part of a motor or motor-compressor that, when properly applied, protects the motor against dangerous overheating due to overload and failure to start.

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electricista

Overload

Interested on how you got #1. It is not correct but interested anyway.

Greg

The answer by the the book is "thermal Protection" art. 100 definitions

As far as your ? 200A 70% =140A=#1awg according to T 310.15(B)(6)

Educate me, what is the answer. I always run the grounded conductor the same size as the ungrounded conductor(s).

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Take the time to tell a Veteran Thank You, You owe him/her at least that much. After all Freedom is not Free.

electricista

Yeah, I should have looked it up but I took a wild stab at it thinking overload protection. Oh well -1 for me

I was afraid I would have to look this up, but I found it. Art. 250.24(C)(1)

Thus, we could technically run a #4 copper conductor . Of course, this would be a rare circumstance and the calculated load would have to be equal to or less than that of a #4 copper.

In almost every resi job I see the grounded conductor is downsized. I typically would run 2/0 copper for the ungrounded conductors and a 1/0 for the grounded conductor for a 200 amp service.

sparkinneed

[quote=Bkessler;55411]Rules are simple, when you answer a question cite article number then ask your own multiple choice question and state what year code was used. this thread hopefully will get people practicing going through the code book fast for exam preparation. After a while hopefully we should get a real good practice test going.


(nec 2005)

Which of the following is not a standard breaker or fuse size?
a)30
b)45
c)175
d)275

sparkinneed

[quote=sparkinneed;61087][quote=Bkessler;55411]Rules are simple, when you answer a question cite article number then ask your own multiple choice question and state what year code was used. this thread hopefully will get people practicing going through the code book fast for exam preparation. After a while hopefully we should get a real good practice test going.


(nec 2005)

Which of the following is not a standard breaker or fuse size?
a)30
b)45

d)275

electricista

Art. 240.6(A) Answer (D)

jfwfmt

(2008 nec)

310.4 Conductors in Parallel.
(A) General.
Aluminum, copper-clad aluminum, or copper conductors of size 1/0 AWG and larger, comprising each phase, polarity, neutral, or grounded circuit conductor shall be permitted to be connected in parallel (electrically joined at both ends).
Exception No. 1: Conductors in sizes smaller than 1/0 AWG shall be permitted to be run in parallel to supply control power to indicating instruments, contactors, relays, solenoids, and similar control devices, or for frequencies of 360 Hz and higher, provided all of the following apply:
(a) They are contained within the same raceway or cable.
(b) The ampacity of each individual conductor is sufficient to carry the entire load current shared by the parallel conductors.
(c) The overcurrent protection is such that the ampacity of each individual conductor will not be exceeded if one or more of the parallel conductors become inadvertently disconnected.
Exception No. 2: Under engineering supervision, grounded neutral conductors in sizes 2 AWG and larger shall be permitted to be run in parallel for existing installations.
FPN to Exception No. 2: Exception No. 2 can be used to alleviate overheating of neutral conductors in existing installations due to high content of triplen harmonic currents.
....
(E) Equipment Grounding Conductors. Where parallel equipment grounding conductors are used, they shall be sized in accordance with 250.122. Sectioned equipment grounding conductors smaller than 1/0 AWG shall be permitted in multiconductor cables in accordance with 310.13, provided the combined circular mil area in each cable complies with 250.122.

620.12 Minimum Size of Conductors.
The minimum size of conductors, other than conductors that form an integral part of control equipment, shall be in accordance with 620.12(A) and (B).
(A) Traveling Cables.
(1) Lighting Circuits. For lighting circuits, 14 AWG copper, 20 AWG copper or larger conductors shall be permitted in parallel, provided the ampacity is equivalent to at least that of 14 AWG copper.


If the test is tricky, the answer can be:

1) 1/0 AWG
2) < 1/0 AWG
3) 2 AWG
4) 20 AWG

/s/ Jim Williams

ralpha494

I thought 620.12 (B) said 24 AWG but after re-reading it I see that it isn't talking about parallel conductors.

Here's two of my favorites:

Using the 2008 NEC:

A restaurant has two (2) 18 kW ranges and two (2) 2 kW appliances, all of which are thermostatically controled. What is the total kVA demand on the service?
A. 32
B. 34
C. 36
D. 40

What is the minimum number of straps required to support 118 feet of straight 2-1/2 inch IMC between two boxes in a hospital corridor?
A. 8
B. 9
C. 12
D. 13

jfwfmt

220.56 and table 220.56 Answer A
342.30(A) and (B)(2) and table 344.30(B)(2) Answer A

nec 2008

What colors are permitted for insulation or or marking of wires greater than #6 for neutral conductors?

A White
B Gray and White
C White and light Blue
D all of the above

JohnJ0906

B - 200.6(B)


Electrical systems shall be connected to earth in a manner that will -

a) limit the voltage imposed by lightning, line surges, or unintentional contact with higher voltage lines
b) stabilize the voltage to earth during normal operation
c) create a low-impedance fault path
d) a + b
e) all of the above

__________________
John from Baltimore
"One day at a Time"
All responses based on the '08 NEC
It's not my fault, it's not my problem, I'm not your solution.

jfwfmt

Actually it is a matter of how you read the question.

1) insulation on any wire size or marking tape on #6 or larger wires
2) insulation color on or marking tape on #6 or larger wires

for 1) interpretation the answer is D
for 2) interpretation the answer is B

I would go for 1) because it has the more obscure part of the code in its answer
/s/ Jim WIlliams

ralpha494

Using the 2008 NEC:

A restaurant has two (2) 18 kW ranges and two (2) 2 kW appliances, all of which are thermostatically controled. What is the total kVA demand on the service?
A. 32
B. 34
C. 36
D. 40

The answer is 36 kW. Read the last sentance in 250.56.

JohnJ0906

OK, I guess it is obscure, because I can't find where light blue is permitted/required for a neutral.

__________________
John from Baltimore
"One day at a Time"
All responses based on the '08 NEC
It's not my fault, it's not my problem, I'm not your solution.