On large service entrance services the neutral can be reduced. The amperage of the service and the voltage of the service and the insulation factor of the 500 MCM conductors need to be stated to answer this question correctly.
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.
Whether you have an overhead or underground feed, that section of the installation is referred to as Service Entrance Conductors. On an overhead installation, it includes the conductors on BOTH sides of the meter, from the service drop conductors (attached at the service head) to the service equipment LINE terminals. On an underground installation, it refers only to the conductors between the meter's LOAD side and the service equipment LINE terminals. The conductors on the LINE side of the meter come from a distribution transformer and are unbroken between the transformer and your meter.
There is no one wire that is rated for 1800 amps. The service will have to be a quad parallel of the conductors. A 600 MCM conductor with an insulation factor of 90 degrees C is rated at 475 amps. This conductor paralleled into four equal lengths will give an ampacity of 1900 amps for each leg of the service.
Need to know what size service is going to be installed at the end of the run.
This answer is taken from the CEC. Table 17 states minimum size of grounding conductors. For a service conductor drawing 400 amps a #3 copper grounding conductor is needed. Also see rules 10-206, 10-700 and 10-812 if you have access to the code book.
4/0 copper phases and neutral
From the question it is hard to establish whether the service size is 350 amps or the service conductors are 350 MCM in parallel. If the service is 350 amps, the grounding conductor is #3 bare copper wire. Parallel 350 MCM conductors will allow for a 600 amp service. The grounding conductor for a 600 amp service is a #1 bare copper wire.
On a 120/240 volt distribution the neutral is sized along with the supply conductors. The sizing is based on the amperage of the service distribution.
The size of wire for service entrance conductors for a 400 amp 3 phase service could be 500 MCM copper. This is very large size wire and difficult to bend and shape, to connect to terminals in the main disconnect and distribution panel. This problem is solved by using parallel conductors or on higher ampacities triple conductors. Using parallel conductors the wire size would be three ought (3/0) copper.
The utility company can provide a 480 volt, single phase service from a single phase transformer, usually with a three wire service. 480 volts is measured between the two line conductors, and 240 volts is measured between either line conductor and the common neutral conductor. The voltage of the line conductors are at 180 degrees with respect to the neutral conductor.
the lights would grow dimmer if the large appliance draws so much current that the resistance of the main electrical service conductors to that current causes a service voltage drop. less voltage means less light. one reason the lights might grow brighter when the large appliance comes on is if the rest of the household electric load (other than the large appliance)is mostly connected to just one of the service conductors, with the large appliance on the other service conductor and the service neutral is marginal or undersized. the neutral carries the unbalanced current of the two service conductors so, without the large appliance on line, the neutral is carrying a large current and the resistance of the undersized neutral to that large current is causing a voltage drop all the time, so lights are dim all the time. when the large appliance comes on line, the unbalance is reduced, the neutral carries less current, the voltage drop reduces and the lights brighten.
The term SN refers to a panel or disconnect switch that has solid neutral bar installed. It is a small bar that allows the service conductors to be bonded to the enclosure at that point.
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.
#2 Copper with TW insulation is required for 100 amp loads #3 Copper with R90 insulation is rated at 105 amps.
Answer for USA, Canada and countries running a 60 Hz supply service.240 volt two wire circuits loads do not need a neutral to operate. A three wire 240 volt circuit that needs a neutral, will have a neutral the same size as the current carrying conductors. In this case a #10.
Whether you have an overhead or underground feed, that section of the installation is referred to as Service Entrance Conductors. On an overhead installation, it includes the conductors on BOTH sides of the meter, from the service drop conductors (attached at the service head) to the service equipment LINE terminals. On an underground installation, it refers only to the conductors between the meter's LOAD side and the service equipment LINE terminals. The conductors on the LINE side of the meter come from a distribution transformer and are unbroken between the transformer and your meter.
service lateral conductors are the underground conductors between the utility electric supply system and the service point, basically the cables that bring power from the transformer to the power meter in an underground service