n you run thhn wire in a cable tray
School question. The answer can be found in your electrical code book.
For a service rated at 400 amps using 500 MCM THHN copper conductors, the minimum size for a copper grounding electrode conductor (GEC) can be determined using the National Electrical Code (NEC) guidelines. According to NEC Table 250.66, for a service of 400 amps, the minimum size for a copper GEC is 4 AWG. However, if the GEC is connected to a ground rod, it must be a minimum of 6 AWG copper.
The conductors of any three phase circuit must be run in the same conduit. If the circuit requires a neutral, it must also run with the conductors in the same conduit. (If they were to be run in more than one conduit or raceway, the circuit would not operate properly.)
Need to know what size service is going to be installed at the end of the run.
When derating THHN wire, you typically refer to the ampacity column in the National Electrical Code (NEC) Table 310.16 (or its equivalent in local codes). This table provides the allowable ampacity for various wire types at different temperature ratings and installation conditions. For derating, you'll adjust the ampacity based on the number of conductors in a raceway, ambient temperature, and insulation type, ensuring compliance with NEC guidelines. Always consult the latest version of the NEC and local amendments for accurate information.
yes
9
THHN is a heat resistant thermoplastic insulated conductor, usually a single conductor. Romex is a brand name for a nonmetallic sheathed cable, it has multiple conductors inside, the insulated ones are insulated with THHN insulation.
According to the 2005 NEC Annex C, table C.1 you are allowed nine #12 THHN conductors in a 1/2" trade size EMT conduit. If your conduit run is any length at all, you would be wise to increase the conduit size to 3/4". as pulling 9 #12's for any length in 1/2" EMT is very difficult.
#8 aluminum thhn 90 degree wire is rated at 30 amps. Remember to de-rate the wire for more that three conductors in a raceway and the second de-rate for the ambient temperature. Most students miss the de-rate for more that three conductors in a raceway.
That depends on the size of the conductor and the type, which is defined by its insulation. With many common large feeder conductors such as THHW, the largest conductor which you can run 8 of is # 2 gauge. Whereas common small branch circuit conductors such as # 12 THHN, you can run 138 ea. through a 2 " conduit. For the complete list, look at the chart titled "Maximum number of conductors in electrical metallic tubing" (EMT) in the National Electrical Code.
Exposed THWN (Thermoplastic High Heat-resistant Nylon-coated) conductors are not suitable for use as they are not rated for exposure to the environment. This can lead to safety hazards such as electrical shocks or fires. It is essential to follow proper installation practices to ensure the safety and longevity of electrical systems.
School question. The answer can be found in your electrical code book.
In a three-quarter inch EMT (Electrical Metallic Tubing), the maximum number of 12 AWG THHN conductors allowed is typically 10, according to the National Electrical Code (NEC) guidelines for conduit fill. However, this number can vary based on factors such as the specific application, bundling, and ambient temperature. It’s always important to consult the current NEC code and local regulations for accurate requirements.
9 - Is this a test answer or do you just want to know for a project you're doing? Take a look at NEC chapter 9 - tables 4 and 5 (in the 2005 edition at least)
For five runs of #12 AWG conductors, a minimum of 1 inch PVC conduit would be required to meet the fill ratio requirements, providing adequate space for the conductors while allowing for future additions or modifications.
THHN wire is a single-conductor wire used for commercial and industrial applications, while Romex wire is a type of electrical cable with multiple conductors used in residential settings. Romex wire is more suitable for residential electrical wiring due to its ease of installation and protection against damage.