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.)
noyou can not
No, the conduit has to be supported individually from a supportive structure. The spacing of the strapping is related to the size of the conduit.
According to the wording ,2 different phase wires "can" run through the same conduit. Not only can they, but if they are part of the same circuit they must. And in cases where conductors are paralleled, meaning more than one conductor per phase as is common in commercial and industrial installations, you put one conductor of each phase and a neutral, if one exists, and a ground in each conduit. Not doing so, meaning to put all of one phase in one conduit, causes a voltage to be induced into the conduit and a tremendous amount of heat builds up. Even when using pvc or other non-metallic conduit, somewhere along the way you have something metallic and have the same problem. To simplify, you must put all conductors associated with the same circuit in the same conduit.
what kind of circuit? if it's a subfeed from one panel to another same size as hot wires. if it's a straight 240 volt circuit #8. depends on what kind of circuit.
Yes, this only adds up to four wires. The wire sizing is dependant on the amperage of the two single phase loads. Remember to calculate the conduit fill of the four wires to make sure that you have the correct size conduit for the installation.
Yes, they all have to be in the same conduit. By placing them all close together there is a cancellation of each conductors magnetic field that surround the conductors when a current flows.
The ground wire and neutral wire are not the same.
If the conduit has reached its limit as to how many wires can be in it, there is only one course of action and that it to install another conduit parallel to the existing one. The electrical code book only allows a certain cross sectional filling of any conduit size. The rule is based on the dissipation of heat from the conductors in the circuits through the conduit walls. Once the wire fill has reached that figure no more wires should be pulled in because of insulation heating. Over time the heating of the insulation could lead to insulation breakdown and then short circuiting of the existing conductors that are in the same conduit.
No you can not mix voltages. That being said if the lower voltage is part of the control circuit from a MCC control centre then yes they can be mixed as the low voltage control is part of the complete system.Composite power & control Teck 90 cable has the power feeders and usually 3/#12 or 3/#14 wires embedded in the same cable. These three wires allow for remote stop - start controls to be mounted neat the motor out in the field.
The simple answer to your question is yes. But there are limits to how many wires can be in any conduit, and the current carrying capacity of the conductors can be affected by distance, ambient temperature, and how many conductors are contained in the same conduit. Other things to consider are, Can you physically fit the wires in there? Would it be easier to run a new conduit? Do you have the manpower necessary to get the work done?
If they are on the same circuit you only need 1 neutral wire in the circuit.