Raceways: RMC, IMC, EMT, PVC, ENT, FMC and LFMC — Uses, Sizes, Bends, Securing and Supporting
"Raceways and Cable Trays" is the first-listed sub-topic of the Wiring Methods area. Almost every raceway question is one of five things: where can I use it, what sizes exist, how tightly can I bend it, how often must I strap it, and can it serve as the equipment grounding conductor. The articles are written on a common template (xxx.10 uses permitted, .12 not permitted, .20 size, .22 fill, .24 bends, .28 reaming/trimming, .30 securing and supporting, .42 couplings, .46 bushings, .60 grounding), so learn the template once and the numbers by raceway. Written from the 2026 text.
NFPA 70 National Electrical Code, 2026 edition · Reviewed 2026-09-19
"Raceways and Cable Trays" is the first-listed sub-topic of the Wiring Methods area. Almost every raceway question is one of five things: where can I use it, what sizes exist, how tightly can I bend it, how often must I strap it, and can it serve as the equipment grounding conductor. The articles are written on a common template (xxx.10 uses permitted, .12 not permitted, .20 size, .22 fill, .24 bends, .28 reaming/trimming, .30 securing and supporting, .42 couplings, .46 bushings, .60 grounding), so learn the template once and the numbers by raceway. Written from the 2026 text.
1. Trade sizes and metric designators — 300.19(B)
| Metric | 12 | 16 | 21 | 27 | 35 | 41 | 53 | 63 | 78 | 91 | 103 | 129 | 155 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Trade | ⅜ | ½ | ¾ | 1 | 1¼ | 1½ | 2 | 2½ | 3 | 3½ | 4 | 5 | 6 |
Designators are identification only — not dimensions. Every article repeats the rule that the number of conductors shall not exceed Chapter 9 Table 1 percentage fill (lesson 3).
This is where the public part ends.
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