Re: 300 KVA XFMR, Disconnect?
Originally posted by kiloamp7:
Your xfmr is delta pri. & wye sec. so OCP protection rules for delta-delta are moot.
I appreciate your concern for my confusion but let me try to restate my real concern.
I understand the difference between "Disconnection Means" and OCP. This particular project I have (which caused my post) is drawn and is referencing the OCP as a disconnect (which will be a breaker disconnect, hence the OCP).
I also understand secondary ties, as defined by 450-6, do not apply in my case because I am not connecting more than one XFMR together.
This posted question originally arose from our Estimator who questioned if this OCP is even needed (which I know it is because it is a delta/wye rather than a delta/delta). This question then evolved to question: if this OCP is not needed would any disconnecting means be needed (like that which is required for motors 430-101 or air conditioners 440-11 as example)?
Article 450 does not require any disconnecting means, probably due to the fact the OCP can be relied on for this function. My case about the delta/wye is resolved, but my concern about a possible delta/delta is essential for a most common scenario, so you see my question is integral not moot.
My question still remains as written in the 5th post of this posting above.