430
When sizing a branch-circuit short-circuit and ground-fault protection for a three-phase AC motor, you would use Table ___________________________.
Table 430.250
The disconnecting means of a hermetic-type compressor shall have an ampacity of at least ___________ of the nameplate rated-load current.
115%
440.12 (A)(1)
Overcurrent protection for generators can be found in _____________?
445.12
What items are NOT permitted to enter or pass through a transformer vault?
Any water pipe or duct system foreign to the electrical installation, other than water pipe providing fire protection or transformer cooling.
430.47
A disconnecting means shall be provided for all ungrounded conductors derived from a stationary battery system with a voltage over _________VDC?
60 Volts Direct Current (vdc)
480.7(A)
The locked-rotor current of a 75HP, 460v, three-phase, Design B motor is ___________ amps?
543
430.251 (B)
When sizing fuses for a branch circuit service a hermetic refrigerant motor-compressor, the device shall never exceed ________% of the rated load current marked on the nameplate.
225%
440.22(A) Ex. 2
Emergency shutdown for other than cord and plug generators must be located ___________
Within (at least) ____________ feet of all other disconnects?
(Two separate code references!!)
445.19(C) & Art. 100
(In Sight From or Within Sight - 50') pg. 44
Where a transformer vault is located on the 2nd floor of a high-rise building, the minimum fire rating of the door into the vault is _________ hours?
3hrs
450.43(A)
in a battery rack, what is the minimum clearance between a cell container and any wall or any structure on the side not requiring access for maintenance?
1"
480.10(C)
Disregarding exceptions, what is the minimum number of overload units required by the NEC to protect a 3-phase motor?
3
430.37
To provide overload protection for small air conditioner motor compressors, fused protection at _________ can be utilized?
125% of the rated current
440.52(A)(3)
When is GFCI 'NOT' required in regards to generator use?
445.20 (A) Ex.
Where a transformer vault is not protected by an automatic fire suppression system, the minimum fire rating for the roof is ________________ hours?
3hrs
450.42
Batteries are permitted to be located where?
in rooms with sufficient diffusion and ventilation of gases from the battery
480.10 (A through G)
In general, a motor disconnecting means must disconnect ______________________?
Motor & Controller
430.75(A)
For hermetic refrigerant motor compressor, the amp rating of the disconnect shall be ____ % of the nameplate rating or the branch circuit selection current, whichever is greater.
115%
440.12(A)(1)
The minimum size conductors needed to connect a three-phase generator to a fused disconnect switch are _______ AWG. The generator is rated for 90 kVa at 480v.
[90,000 / (480x1.732)] = 108.26a
108.26 x 115% (1.15) = 124.5a
=#1AWG
445.13
310.16 Ampacity Table
A fused safety switch feeds a 480-208Y/120v, 3ph, 30kVa transformer. The transformer supplies power to a 3ph 100a main breaker panel. According to 430.3, the fuses in the safety switch are permitted to be not larger than _______ amps so that the transformer is adequately protected against overload.
I (pri) = [30,000 / (480x1.732)] = 36.08A
OCPD = 250% (2.50) x 36.08 = 90amps
450.3(B) & 240.6
What size flexible cable are permitted within the battery enclosure.
2/0 AWG and larger
480.12
What is the minimum Locked-Rotor KvA for a Type S motor rated at 37 HP?
Type S is 16-17.99 kVa per HP, Minimum is 16 x 37hp = 592kVa
Table 430.7(B)
When cord connected window (room) air conditioner is the only connected load, the current drawn by the unit shall not exceed ______ % of the branch circuit rating.
80%
440.62(B)
The minimum size conductors needed to connect a three-phase generator to a fused disconnect switch are _______ AWG. The 3ph, 300kVa generator is rated for at 480v.
[300,000 / (480x1.732)] = 360.84a
360.84 x 115% (1.15) = 414.97a
= 600kcmil
445.13 & 310.16
The maximum size circuit breaker permitted by Note 1, NEC table 430.3(A), to protect the primary of a 4160v to 480v, 3ph, 75kVa transformer is _____ amps?
Transformer has an impedance of 1.7% and is installed in a nonsupervised location.
I (pri) = [75000 / (4160x1.732)] = 10.409A
OCPD = 6.00 x 10.409 = 62.454A = 70Amp
next standard size
450.3(A) & 240.6
(DOUBLE JEOPARDY)
Art. 690
A rapid shutdown switch on a PV array shall have a label that includes?!
Lable must also be what?!
RAPID SHUTDOWN SWITCH FOR SOLAR PV SYSTEM
WHITE ON RED
(STICKER OR LABEL appropriate for the location)
690.12(D)(2)