Short answer: Article 600 requires a sign outlet at each tenant entrance of commercial buildings and occupancies accessible to pedestrians, on a branch circuit rated at least 20 A that supplies no other load (NEC 600.5), and a disconnect for each sign (NEC 600.6). Article 620 requires a single disconnecting means for each elevator’s main power supply (NEC 620.51) and allows demand factors for feeders that supply several elevators (NEC Table 620.14). Article 670 sizes the supply conductors for an industrial machine at 125% of the resistance heating load, plus 125% of the largest motor, plus the rest of the motors and loads (NEC 670.4).
PSI lists special occupancies and miscellaneous equipment among the topics in the Special Occupancies, Equipment and Conditions subject area of the Texas Journeyman exam: 6 scored NEC Knowledge questions and 3 in Calculations. PSI does not say how many cover signs, elevators or machinery alone. The Texas Journeyman Practice Pack has 1,000 original questions and 10 timed mock exams in the real two-part format, with step-by-step solutions for every calculation. Try free practice questions without signing up. Get the full pack for US$39 with one payment.
Tsai Electro is an independent learning site. Not affiliated with TDLR, PSI or NFPA. We explain the ideas in our own words and do not reproduce NEC text. Check every rule and table value in your own 2026 NEC, follow the equipment manufacturer’s instructions and nameplate, and follow your supervisor and the local inspector.
Three articles, one idea
These three articles look unrelated, but each adds rules for equipment that the general chapters do not fully cover.
| Article | Covers | What exam questions usually ask |
|---|---|---|
| 600 | Electric signs and outline lighting | Sign outlet at tenant entrances, sign circuit rating, disconnect location, markings |
| 620 | Elevators, escalators, moving walks and similar equipment | Disconnect type and location, feeder demand factors |
| 670 | Industrial machinery | Supply conductor and overcurrent sizing, nameplate data |
Article 600: signs
- Sign outlet at each entrance. Each commercial building and each commercial occupancy accessible to pedestrians needs at least one outlet for sign or outline lighting at an accessible location at the entrance to each tenant space (NEC 600.5). The branch circuit for that outlet is rated at least 20 A and supplies no other load. The section has exceptions, such as for service hallways and corridor entrances, so read them.
- Disconnect. Each sign and outline lighting system needs a disconnecting means that opens all ungrounded conductors (NEC 600.6). It is generally located within sight of the sign, or it must be capable of being locked in the open position. Read 600.6 for the conditions, including signs controlled from a remote location.
- Markings. Signs are listed and marked, including the manufacturer’s name and the input current, and the section adds markings for field-installed parts (NEC 600.4).
Article 620: elevators
- Disconnect. Each elevator needs a single means to disconnect all ungrounded main power supply conductors (NEC 620.51). It is a fused motor circuit switch or a circuit breaker capable of being locked in the open position, located where it is readily accessible to qualified persons. Article 620 adds rules on where it may be located and how it is identified, and it does not disconnect the lighting and ventilation circuits for the car, which have their own disconnects.
- Feeder demand factors. A feeder supplying more than one elevator may use demand factors from Table 620.14, which get smaller as the number of elevators grows. Open the table in your NEC to read the factor for the number of elevators on your feeder.
Article 670: industrial machinery
Industrial machinery has a nameplate that shows the supply voltage, phase, frequency, full-load current, the maximum overcurrent device rating and the short-circuit current rating, among other data. The supply conductors are sized from that data:
- 125% of the full-load current of all resistance heating loads,
- plus 125% of the full-load current of the highest rated motor,
- plus the full-load current of all other connected motors and apparatus that may run at the same time (NEC 670.4).
The available fault current at the machine must not exceed the machine’s marked short-circuit current rating (NEC 670.5).
Worked example 1: sign circuits in a strip center
A new strip center has three tenant spaces, each with a pedestrian entrance from the parking lot. How many sign outlets are needed, and what is the minimum circuit rating?
- One sign outlet at the entrance to each tenant space: 3 outlets.
- Each required sign outlet is supplied by a branch circuit rated at least 20 A that supplies no other load. The question asks for outlets, not circuits.
- Check: a general-purpose receptacle for a window display would be another load, so it cannot go on the sign circuit. Feed it from a different branch circuit.
Worked example 2: supply conductors for a machine
An industrial machine nameplate shows a 10 A resistance heating load, one 28 A motor (the largest), one 12 A motor and 6 A of other apparatus, all running together. Use copper conductors with 75°C insulation and 75°C terminals, no more than three current-carrying conductors, a 30°C ambient, and no correction or adjustment. Size the copper supply conductors.
- Heating at 125%: 10 × 1.25 = 12.5 A.
- Largest motor at 125%: 28 × 1.25 = 35 A.
- Others at 100%: 12 + 6 = 18 A.
- Total: 12.5 + 35 + 18 = 65.5 A.
- From the 75°C copper column of Table 310.16: 6 AWG is 65 A, which is less than 65.5 A. 4 AWG is 85 A, which meets it. Use 4 AWG copper.
This is a 0.5 A miss on 6 AWG. Questions like this test whether you round the conductor up instead of rounding the load down.
Check yourself
- Minimum rating of the branch circuit for a required sign outlet? 20 A, supplying no other load.
- Does the elevator main disconnect turn off the car lighting? No. Car lighting and ventilation have their own disconnects.
- In a machine supply calculation, which motor gets 125%? The highest rated motor. The rest are added at 100%.
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Tab Articles 600, 620 and 670 before exam day
NFPA 70, National Electrical Code, 2026 Edition (softcover). These articles sit far apart in the book, so find them fast: highlight the sign outlet rule in 600.5, the disconnect rule in 620.51 and the supply conductor rule in 670.4. The Texas exam is open book. PSI allows a soft-bound NEC with highlighting, underlining and notes made in advance. Loose-leaf, spiral-bound and ring-bound copies are not allowed, and only permanent index tabs made or supplied by the NEC publisher are permitted; homemade and third-party tabs are not.
FAQ
Does every commercial tenant need a sign circuit?
Each commercial building and occupancy accessible to pedestrians needs at least one sign outlet at the entrance to each tenant space, on a branch circuit rated at least 20 A that supplies no other load. The section has exceptions, such as for entrances from service hallways or corridors.
Where does the sign disconnect go?
Each sign needs a disconnect that opens all ungrounded conductors. It is generally within sight of the sign, or it must be lockable in the open position. Section 600.6 has the conditions.
How do you size the wire for industrial machinery?
Add 125% of the resistance heating load, 125% of the largest motor, and 100% of the other motors and loads that run together. Then pick the conductor from the correct temperature column of Table 310.16.
Are signs and elevators on the Texas Journeyman exam?
PSI lists special occupancies and miscellaneous equipment in the Special Occupancies, Equipment and Conditions subject area, which has 6 scored NEC Knowledge questions and 3 scored Calculations questions. PSI does not say how many cover signs or elevators alone.
Sources checked October 2026
- PSI Candidate Information Bulletin, Texas electrician examinations (updated September 15, 2026): https://test-takers.psiexams.com/api/content/bulletin/1682
- NFPA 70, National Electrical Code, 2026 Edition, Articles 600, 620 and 670
