Transfer Switch

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Gaffen99

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new jersey
Can I install a 200 amp transfer switch on an existing 100 amp main breaker service. Thought is the customer is thinking of upgrading at a later date. The 100 amp main breaker is still protecting the wire, so the transfer switch is just a switch. Tap rule?
Thx
 
Gaffen99 said:
Can I install a 200 amp transfer switch on an existing 100 amp main breaker service. Thought is the customer is thinking of upgrading at a later date. The 100 amp main breaker is still protecting the wire, so the transfer switch is just a switch. Tap rule?
Thx
Click to expand...

No tap rules needed, you can always install a switch rated move than the circuit. :)
 
Gaffen99 said:
Can I install a 200 amp transfer switch on an existing 100 amp main breaker service. Thought is the customer is thinking of upgrading at a later date. The 100 amp main breaker is still protecting the wire, so the transfer switch is just a switch. Tap rule?
Thx
Click to expand...


Will this be set up as a service rated transfer switch with a 200 amp OCPD?
 
infinity said:
Will this be set up as a service rated transfer switch with a 200 amp OCPD?
Click to expand...

It is a service rated switch. I left the wiring rated at 100 amps and install 2/2/2/4 to the existing 100 MB panel and ran the grounds to the transfer switch. The rating of the actual service hasn't changed, it just has a 200 amp breaker/switch in line. The OCP device would be the 100 amp MB in the panel.
 
But it sounds like IT has changed. You stated you ran the grounds to the transfer switch. Did you also run the GEC to the transfer switch? I will assume when you say Grounds that is what you mean.

Sounds to me like your panel inside is now a remote distribution panel and the panel outside is your service rated equipment. If this is the case, you would need your GEC at the service disconnection location and this would now be your main service. You stated you ran (4) conductors inside to the existing panel, which is now a distribution panel and so you treat it as such (your separations as you know).

Anyway.....unless I am totally misreading this post (and I am sure someone will tell me) I am slightly concerned in regards to 230.91 based on how your last post explained it.
 
Gaffen99 said:
It is a service rated switch. I left the wiring rated at 100 amps and install 2/2/2/4 to the existing 100 MB panel and ran the grounds to the transfer switch. The rating of the actual service hasn't changed, it just has a 200 amp breaker/switch in line. The OCP device would be the 100 amp MB in the panel.
Click to expand...
It appears that the transfer switch is the service disconnect and it has a 200 amp OCPD. The wire from the service point to the line side of the transfer switch needs to be 200 amp wire. From the transfer switch to the 100 amp panel the tap rules may permit you to use 100 amp wire.
 
don_resqcapt19 said:
It appears that the transfer switch is the service disconnect and it has a 200 amp OCPD. The wire from the service point to the line side of the transfer switch needs to be 200 amp wire. From the transfer switch to the 100 amp panel the tap rules may permit you to use 100 amp wire.
Click to expand...

The service is still protected by the main in the panel, and I'm wondering why I would need a larger wire if the ampera
ge would not be any higher than 100 amps?
 
Gaffen99 said:
The service is still protected by the main in the panel, and I'm wondering why I would need a larger wire if the amperage would not be any higher than 100 amps?
Click to expand...

Because the transfer switch is now the service disconnect which has a 200 amp OCPD protecting the service entrance conductors which are only 100 amps.
 
infinity said:
Because the transfer switch is now the service disconnect which has a 200 amp OCPD protecting the service entrance conductors which are only 100 amps.
Click to expand...

Where in his scenario did the service conductors loose their 100 amp protection?


JAP>
 
jap said:
Where in his scenario did the service conductors loose their 100 amp protection?


JAP>
Click to expand...
The service conductors have to be protected by the service OCPD. There is no provision that permits an OCPD on the load side of the service equipment to protect the service conductors. The service OCPD is now a 200 amp device and requires 200 amp conductors.
 
don_resqcapt19 said:
The service conductors have to be protected by the service OCPD. There is no provision that permits an OCPD on the load side of the service equipment to protect the service conductors. The service OCPD is now a 200 amp device and requires 200 amp conductors.
Click to expand...

I see now.

JAP>
 
Gaffen99 said:
What if I had a 200 amp disconnect in line with a 100 amp MB panel, how would you handle that? Would you wire with a 200 amp rating?
Click to expand...
If you put 200 amp fuse in the disconnect you would have to have 200 amp wire. Note that the service OCPD is required to be a part of service disconnect or immediately
adjacent thereto.

You could install a 200 amp non-fused disconnect with a 100 amp main breaker panel next to the disconnect and use 100 amp wire. Note that, in general, you can't use a non-fused disconnect if the available fault current exceeds 10,000 amps.
 
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