Transformer Disconnect Switch
- Thread starter twada
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Re: Transformer Disconnect Switch
No, there should not be any switch on the primary side except the overcurrent device.
The switch would have to safely carry the inrush current. Unless specifically tested for this function, the switch will compromise the continuity of service.
No, there should not be any switch on the primary side except the overcurrent device.
The switch would have to safely carry the inrush current. Unless specifically tested for this function, the switch will compromise the continuity of service.
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- Massachusetts
Re: Transformer Disconnect Switch
No there is not a code section saying you do not have to put a disconnect switch.
What matters is there is not a code section saying you must put a disconnect switch.
No there is not a code section saying you do not have to put a disconnect switch.
What matters is there is not a code section saying you must put a disconnect switch.
Re: Transformer Disconnect Switch
If I were the inspector I would call this as follows; I would apply 110.3.A&B.
This is more an engineering design issue, but it is a fundamental of electrical application.
The pounding of slip fit contacts, in a switch, will likely shorten the life of the switch, even though it would not be hit often.
All electrical equipment, with moving parts, should be kept to the minimum of what is necessary.
If I were the inspector I would call this as follows; I would apply 110.3.A&B.
This is more an engineering design issue, but it is a fundamental of electrical application.
The pounding of slip fit contacts, in a switch, will likely shorten the life of the switch, even though it would not be hit often.
All electrical equipment, with moving parts, should be kept to the minimum of what is necessary.
Re: Transformer Disconnect Switch
Chapter 4 of the NEC deals with "Equipment for General Use". Anything requiring a disconnecting means is specified in Articles 400 through 490. Article 450 deals with Transformers specifically and it does not call for disconnect means on the primary as long as you have the required overcurrent protection.
Chapter 4 of the NEC deals with "Equipment for General Use". Anything requiring a disconnecting means is specified in Articles 400 through 490. Article 450 deals with Transformers specifically and it does not call for disconnect means on the primary as long as you have the required overcurrent protection.
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