Mike Dolt Enterprises
Mike Dolt Enterprises
User: ERP, Location: California
Asked on: Thursday, March 31, 2011 at 5:25 pm EDT
Answered on: Thursday, May 23, 2024 at 6:10 pm EDT
Question: Hi:I have been coming to Mike Holt?s website and occasionally lurking here when I have an electrical question and have always readily been able to find my answers, but now I am into some stuff where Google and lurking are not going to answer my questions!We have just begun running a 480v 3 phase generator on a trailer, then main power cables to a distribution box, which then is distributed to power multiple 460v heaters at industrial jobsites.As using this type of equipment and working with this kind of voltage is new for our firm, I have a host of questions.First Question: The main power cords are either 50 or 75 foot lengths of Carol 6/4 600VAC with Hubbell 50amp ends. (Photos below) The challenge is we are frequently running these a lot further than 75 feet, so the manufacturer tells us to daisy chain these together! I have always understood daisy-chaining was a no-no, but they say this is fine up to 800 feet with these cords (daisy-chaining up to 16 cords!) From a pure safety standpoint my biggest concern is with these cords being disconnected or re-connected with a 480V load on them. So is this legal and safe or not?Second Question: I am being further told we are to run these up the sides of buildings daisy-chained. Even with some safety straps I cannot see how this can be safe or legal!I have more questions, but I figure I will leave it at these two for this first post!Thanks!Eric
First Question: Daisy-Chaining Power Cords
According to the National Electrical Code (NEC): 400.8 Prohibits the use of electrical cords for permanent wiring. 240.4(A)(4) Permits the use of flexible cords as temporary power connections where the use of permanent wiring or fixed cables is impractical. However, such cords cannot be used where they are subject to physical damage.In this case, the power cords are being used for a temporary power connection. However, since they are being daisy-chained, they are potentially subject to physical damage. Therefore, daisy-chaining the cords is technically not permitted by the NEC.Additionally, daisy-chaining cords can create safety hazards, such as: Reduced voltage at the end of the chain Overheating and fire risk Loose connections Accidental disconnection, resulting in electric shockSecond Question: Running Cords Up Buildings Daisy-Chained 334.30(B) Requires temporary wiring to be securely supported.In this case, it is unlikely that the daisy-chained cords can be securely supported when running up the sides of buildings. Therefore, running the cords up buildings daisy-chained is also not permitted by the NEC.
Recommendations
Use a single, continuous length of power cord that is rated for the required voltage and current. If a longer cord is needed, consider using a heavier gauge wire or a different type of cable. Secure the cords properly using conduit, cable supports, or other approved methods. Inspect the cords regularly for damage and replace if necessary. Train personnel on the proper handling and use of electrical cords.
Additional Questions:
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