Basic question about dielectric ratings for wire

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Basic question about dialectric ratings for wire

well, this is a rather basic question. Say I have two +-400 VDC lines, each of which are running on a cable that is rated to 600 VDC. Is it safe to run these cables right next to each other for a few feet inside of a umbilical-type power cable? I would assume so, since the total potential is 800 V and each cable can contain its own share of the 400 V...If I wanted to be extra cautious, would placing the cable in teflon tubing be one way to go, or totally not necessary?

Thanks!
 
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According to this link http://www.motioncontroluniversity.com/training/handbook/cabling/voltagerating.html

"The specified voltage rating is defined in relation to the conductor and an adjacent item. For example, the single conductor has the insulation rated between itself and any other device (shield or other device capable of developing a voltage potential) and the outer jacket has no insulation rating recognizable by UL and therefore cannot be considered as a factor in the rating. According to UL, it is just a protective and binding element."

So, the answer to your first question would be yes. 1200V would be the maximum allowable potential difference between the conductors of two wires that both have 600V insulation ratings. Putting teflon between them would expensive and unnecessary. If you want to be extra cautious you would either physically separate each wire or install another layer of insulation around each wire where they run in close proximity. I would opt for another protective layer of insulation.
 
Hi,
in the UK we use twin and earth.
the live and neutral are insulated and the earth is uninsulated.
Each core insulation must meet the voltage requirement between core and earth. Even if the two cores had opposite phase on them their core to earth insulation would ensure that core to core worst case also complied.

However, add an extra outer insulation. This provides physical protection to the main core insulators ensuring they stay up to specification. All our mains cables must be double insulated when outside a protective enclosure.
 
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