The way I do these is to install a triple lug on X0.
One conductor is the secondary grounded conductor (neutral).
The next conductor is the GEC.
The third is the bonding jumper.
I do the same as Electure, for the X-0 terminal.
When Parallel Feeders are used, then it's time for a 4 position Lug.
What really sucks for terminating to those larger Lugs, is when the terminal studs are
sooooooo low and close to the bottom mesh of the Transformer - such as the Transformer we are using for this thread's example Guienna Pig.
Federal Pacific's Transformers have the terminations nice and high, which makes it
soooooo much nicer to land large Feeders; whereas the typical GE, MGM and ACMEs are about 4" above the bottom mesh!
Okay- What are doing for transformer overcurrent?? I say we protect the primary at 125% of it's capacity and forgo protection of the secondary. If that's the case we can protect the primary at 125% x 90 = 112a. so we use a 125a overcurrent protection. gives me a #1/0 wire. Now we don't have to protect the secondary. This overcurrent protects the transformer. If we go over 125a. on the primary we would have to add secondary protection.
Not sure if we can use the Primary OCPD to protect the Secondary Feeders on this particular Transformer - as it is a 208/120 VAC Secondary - not a "Single Voltage Secondary".
I think this would be in Article 240, maybe something like section 240-3, and about ¾ of the way down through the list of items (Transformer Secondary Conductors' Overcurrent Protection).
Shooting from the hip here, as my code books are "Not Readilly Accessible At This Time"
(read: NEC and CEC books are in the Van; I'm too lazy to go get one at this time...)
Article 450 would only mention Primary or Secondary OCPD to be no more than 125% FLA - with certain exceptions, so there's no need to venture into the "400's" to reference this Secondary Voltage thingee.
Feel free to debunk this and reply with many, many swear words if I am wrong about the OCPD stuff.
. Question #2 is I cannot make out what is in the conduit on the bottom left side. It appears to be the gec. If so where is it terminated and would the bonding jumper sent to the bushing on that conduit entry need to be the same size as the gec?
Here's something overlooked so far - and a good question too!
Would the Bonding Bushing for the GEC's Conduit need to be bonded with a Conductor equally sized to the GEC, or will a Conductor sized similar to the EGC used with the Secondary Feeders be Okee-Dokee?
Would a "Wedge Screw Locknut" be acceptable, in lieu of a Bonding Bushing?
("Wedge Screw Locknut" = Locknut with a set screw cast into it at an angle, which is "Wedged" against the enclosure when the Locknut is completely set).
Bonding the Conduits for the Feeders is a No-Brainer (as far as sizes go that is!).
Blast away
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Scott35
