Yes, there will be a de-rate applied to this type of installation. In the electrical code book the amperage rating of conductors is for allowable ampacities for not more than three copperconductors in raceway or cable. This is based on an ambient temperature of 30 degrees C.
If the ambient temperature of the conductors where the raceway is installed is over 30 degrees C the conductor amperages have to be reduced.
Where the number of conductors are from 4 to 6 conductors in a raceway, the conductors amperage has to be reduced by .8
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.)
There is no such thing as a 'phase conductor'. The correct term is 'line conductor'. Line conductors are the three energised conductors that supply a three-phase load.
Yes. The thing that has to be closely watched is the load on the conductors. The conductors will have to be de-rated as the code only gives amperage rating for three conductors in a raceway. So watch the connected amperage to each load and fill the conduit accordingly. This supersedes the conduit fill requirements rule.
'Line conductors' are the three 'hot' conductors (A-B-C) that connect a three-phase supply to a three-phase load. In some cases, a pair of line conductors (e.g. A-B, B-C, or C-A) is used to supply a single-phase load. A 'line fault' can be a short-circuit fault between all three, or any two, of these line conductors -whether they supply a three-phase load or a single-phase load.
YesIn Canada the answer is no. Triplex is an aerial rated set of conductors that are used to bring the voltage from the utilities pole to the service drop at the home. Triplex consists of two ungrounded conductors wrapped around a neutral steel supported conductor. These conductors can be used on higher current capacities due to the direct cooling of the conductors by the surrounding air. This is why you will see a service drop of number 6 conductors supplying a 100 amp service. For a three phase four wire system quadplex is used to make three phase connections to commercial and industrial services.
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.)
There is no such thing as a 'phase conductor'. The correct term is 'line conductor'. Line conductors are the three energised conductors that supply a three-phase load.
They can be either separated or combined. What governs the choice is the size of the service and the conductors feeding the service and the ability to physically connect metering equipment to larger size conduits. When paralleling conduits make sure all the phase wires are in their individual conduits to cancel the field effect of the wires. Eg. conduit 1 - L1 + L2 + N , conduit 2 - L1 + L2 + N. Likewise with three phase, conduit 1 - L1, L2, L3, conduit 2 L1, L2, L3.
The number of current-carrying conductors allowed in a conduit before derating is specified by the National Electrical Code (NEC). Generally, if you have more than three conductors in a conduit, you need to start derating the ampacity of the conductors. Specifically, for more than three conductors, the ampacity of each conductor must be reduced based on the number of conductors present. For example, with 4 to 6 conductors, the ampacity is typically reduced to 80%, and with 7 to 9 conductors, it’s reduced to 70%.
Yes. The thing that has to be closely watched is the load on the conductors. The conductors will have to be de-rated as the code only gives amperage rating for three conductors in a raceway. So watch the connected amperage to each load and fill the conduit accordingly. This supersedes the conduit fill requirements rule.
'Line conductors' are the three 'hot' conductors (A-B-C) that connect a three-phase supply to a three-phase load. In some cases, a pair of line conductors (e.g. A-B, B-C, or C-A) is used to supply a single-phase load. A 'line fault' can be a short-circuit fault between all three, or any two, of these line conductors -whether they supply a three-phase load or a single-phase load.
For a three-phase, three-wire, system there are three conductors called 'line conductors', and there is a voltage between any pair of line conductors, so there are three voltages.For a three-phase, four-wire, system there are four conductors: three 'line conductors' and a 'neutral' conductor. So there are three line voltages (voltages between lines) and three phase voltages (voltages between any line conductor and a neutral conductor).
The conductors between a three-phase supply and a three-phase load are called line conductors not phase conductors, and the voltage measured between them are line voltages, not phase voltages. In the case of a delta supply, the line voltages are numerically equal to phase voltages, but the name remains the same!I have to admit that many people call line conductors 'phase conductors', but many people also say 'irregardless' -that doesn't make it a real word!!
4/0 gauge wire, depending on its insulation type is rated from 230-260 amps. Assuming you are running a new power supply with the 4/0 wire, you will have a minimum or three 4/0 conductors and a ground wire for a single phase power supply and four conductors with ground for a three phase power supply. Three 4/0 wires require a minimum 2 inch conduit. Four 4/0 wires require a minimum 2 and 1/2 inch conduit. These conduit sizes I'm quoting come directly from the NEC, the National Electric Code. These sizes of conduit are determined by the basic rule that all the conductors in a conduit are not to exceed 40% of the volume of the pipe. The other 60% of air space is required for heat dissipation.
The sizing of conduit systems that wire has to be pulled into is dependant on the physical size of the conductor being drawn into the conduit. The second governing factor is the conductor count of the specific conductor that is needed. A 500 MCM copper conductor with an insulation factor of 90 degrees C is rated at 430 amps. This is where the conductor count is need by the service, as to whether the service is single or three phase. In this specific case, the electrical code will allow both single and three phase installations to use the same size conduit. A maximum total of four 500 MCM conductors can be drawn into a 78 mm diameter conduit.
YesIn Canada the answer is no. Triplex is an aerial rated set of conductors that are used to bring the voltage from the utilities pole to the service drop at the home. Triplex consists of two ungrounded conductors wrapped around a neutral steel supported conductor. These conductors can be used on higher current capacities due to the direct cooling of the conductors by the surrounding air. This is why you will see a service drop of number 6 conductors supplying a 100 amp service. For a three phase four wire system quadplex is used to make three phase connections to commercial and industrial services.
A ground, or earth, conductor is never included in the conductor count. So, a three-phase, three-wire, system has three line conductors, whereas a three-phase, four-wire system, has three line conductors and a neutral conductor.