transfer switch instalation
#1
09-17-02, 02:01 PM
transfer switch instalation
I want to have an electrician install a tranfer switch for a generator that I will purchase. However, I want to start the generator on one side of my home while the electric panel is on the other side. Is there a limit on the distance between the transfer switch and the electric panel? Can limitations be overcome by using a heavier guage cable?
#2
09-17-02, 04:36 PM
Tranfer switch:
The transfer switch must be installed sufficiently remote from the main disconnect for normal supply to minimize the possibilty of simultaneous interuption of supply.
The generator can be installed any location.
If the conductors from the generator enter the building at its location then they will need a disconnect installed either inside, or outside, nearest the point of entrance.
unless they meet any of the following conditions:
230.6 Conductors Considered Outside the Building.
Conductors shall be considered outside of a building or other structure under any of the following conditions:
(1)Where installed under not less than 50 mm (2 in.) of concrete beneath a building or other structure.
(2)Where installed within a building or other structure in a raceway that is encased in concrete or brick not less than 50 mm (2 in.) thick.
(3)Where installed in any vault that meets the construction requirements of Article 450, Part III.
(4)Where installed in conduit and under not less than 450 mm (18 in.) of earth beneath a building or other structure.
Yes distance can be overcome by increasing the wire size
Have you electrician do a voltage drop, then size conductors porperly.
The generator can be installed any location.
If the conductors from the generator enter the building at its location then they will need a disconnect installed either inside, or outside, nearest the point of entrance.
unless they meet any of the following conditions:
230.6 Conductors Considered Outside the Building.
Conductors shall be considered outside of a building or other structure under any of the following conditions:
(1)Where installed under not less than 50 mm (2 in.) of concrete beneath a building or other structure.
(2)Where installed within a building or other structure in a raceway that is encased in concrete or brick not less than 50 mm (2 in.) thick.
(3)Where installed in any vault that meets the construction requirements of Article 450, Part III.
(4)Where installed in conduit and under not less than 450 mm (18 in.) of earth beneath a building or other structure.
Yes distance can be overcome by increasing the wire size
Have you electrician do a voltage drop, then size conductors porperly.
#3
09-17-02, 05:08 PM
New to 2002 NEC:
Also new in the 2002 NEC:
445.13 Ampacity of Conductors.
The ampacity of the conductors from the generator terminals to the first distribution device(s) containing overcurrent protection shall not be less than 115 percent of the nameplate current rating of the generator. It shall be permitted to size the neutral conductors in accordance with 220.22. Conductors that must carry ground-fault currents shall not be smaller than required by 250.24(B). Neutral conductors of dc generators that must carry ground-fault currents shall not be smaller than the minimum required size of the largest conductor.
Exception: Where the design and operation of the generator prevent overloading, the ampacity of the conductors shall not be less than 100 percent of the nameplate current rating of the generator.
445.13 Ampacity of Conductors.
The ampacity of the conductors from the generator terminals to the first distribution device(s) containing overcurrent protection shall not be less than 115 percent of the nameplate current rating of the generator. It shall be permitted to size the neutral conductors in accordance with 220.22. Conductors that must carry ground-fault currents shall not be smaller than required by 250.24(B). Neutral conductors of dc generators that must carry ground-fault currents shall not be smaller than the minimum required size of the largest conductor.
Exception: Where the design and operation of the generator prevent overloading, the ampacity of the conductors shall not be less than 100 percent of the nameplate current rating of the generator.
#4
09-18-02, 07:33 AM
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Re: transfer switch instalation
Originally posted by pmurphy
I want to have an electrician install a tranfer switch for a generator that I will purchase. However, I want to start the generator on one side of my home while the electric panel is on the other side. Is there a limit on the distance between the transfer switch and the electric panel? Can limitations be overcome by using a heavier guage cable?
I want to have an electrician install a tranfer switch for a generator that I will purchase. However, I want to start the generator on one side of my home while the electric panel is on the other side. Is there a limit on the distance between the transfer switch and the electric panel? Can limitations be overcome by using a heavier guage cable?
You want to keep the distance between the transfer switch and the origin of the circuits it will serve as short as you can for operational reasons. Unless the generator is sized to carry the entire load you will need to shut off the circuts that you don't want to use under emergency power to avoid overloading the generator. Having done that and thrown the transfer switch to it's center off position you then start the generator. You then throw the transfer mechanism to the connect the generator to the load.
The only limitation between the transfer switch and the power source is the practical limitations caused by voltage drop. So, yes, you can overcome the voltage drop by sizing the cable appropriately.
--
Tom
