Power Supply Distance in Pullbox

Depends...

The following is based on Canadian code...

Note: This reply was based on your first question, that question appears to have been deleted.

If the source of the 220v feed is from the same source as the 440v feed, as in one half of a 440v center tapped winding on a transformer, then yes. If not... then no. In short, they must be from the same "system".

There are ways of accomplishing this when the conductors are from separate systems, but, it requires a metal barrier in the raceway or other protective means such as cable armour between the conductors. See CEC rule 12-904(2) for provisions that would allow this practice.

Now... generally speaking, when it comes to such matters, the CEC and NEC are pretty much in sync with each other. Having said that... why not call the AHJ in your region for guidance. Believe me... they would rather answer your questions upfront then deal with it afterwards.

Please define your use of "power supply". If simply talking about 2 different voltages, like 24 volts and 120 volts in same conduit, all conductors must have the voltage rating of the highest voltage in the conduit (120 volts). Are you talking about a Feeder(s) to a building? To a subpanel(s)? The fill requirements are irrelevant, and must be observed regardless.

Please clarify your question.

If I understand well you need to distribute two power lines and are planning to use the same pull box.

After all it is bad practice and prohibited by several local and international regulation.

If you do, they must be completely separated in the box and clearly marked to which system they belong. And you need to adapt the drawings and get the system approved before you go live.

Yearly several maintenance persons die due this type of bricolage. They look on the plan, decide that they should cut a certain system when opening that box and inside they find more than should be. While trying to find out which cable they should cut they get electrocuted as they assumed that the power was switched off (they did themself so why checking again?).

North of 60 is correct. The US requires the same.

Also all conductor insulation must be the same voltage rating and do not mix un-fused conductors with fused (protected) conductors. Also you must meet all wire bending radius and conduit entry for minimum pullbox sizing in NEC 314.28

If you are using a physical barrier to separate conductors, remember you have to meet all the requirements of 314 in each section since it becomes two boxes in one.

Thanks for the reply.they are inserted in different conduits but after meeting the standartd distance of laying,I just install 1 pull box with the correct calculation based on NEC 314.28.It happens that inside the pullbox,it had a certain gap based on what I calculated using the standard calculation of NEC 314.28.Pls. verify.

If I saw this done this way on a job I inspected, in Canada, I would have to reject it.

A "pullbox" is considered a raceway under the code and how you have installed the conductors in it, is not code compliant.

Are you a licensed electrical contrator, or working for a licensed electrical contractor? If you are, check with the local AHJ.

If not either, you are violating the law by performing work without a license.

I cannot provide any furthur instructions till I know your status, to do so would be complicity.