Been having a issue with my 73 sat keep burning up my field wire over the engine this past time I had it done at a shop assuming I was doing something wrong Today it is once again fried the wire to battery is hot but you can hold it and the wiring near the bulk head is hot after just 15 minutes was told the alternator could be the cause but it is steady 13.9-14.2 constant output regulator I have checked into all the wiring as some had smoked in the bulkhead connector. changed it out and went with using straight from relay where needed any idea's where to look besides the alt I will check starter wires too Thanks!

Paul, more detail on how you have it wired & which wire(s) are getting hot/burning up. You have the blue 732 (iirc) reg?

Either there is too much current thru the wire (short) or the wire is undersized.

You post is a bit confusing though. Is the measured voltage at the battery 13.9-14.2 at idle or is the alternator supposed to be regulated to 13.9-14.2V? What is this relay you speak of and how is it wired?

A shorted field in the alternator can cause too much current to be flowing in the field wires. The voltage output can still be okay.

The field wire is only supposed to see switched 12 volt power from the run side of the ignition switch to energize the alternator, the power coming out of the big terminal on the alternator needs to go the battery post at the starter relay terminal and not through the ammeter (if you still have one)

If its still the stock setup then the alt output from the output wire does go back through the ammeter. If its been modified it may not as that gets changed most of the time when modified.
But I agree we need more details so we can be sure if your talking about one of the field wires or the alt output wire. Does it use an electronic voltage reg or mechanical ? Ron

ammeter is by passed the wiring burned is blue field wire that is connected to top term of alt the battery output wire is getting hot also. Thanks for the replies and keep them coming

trying to grasp if the constant output reg is overcharging but people have used them with no probs or if something is dead shorted in the field circuit (I'm thinking that) making the alt overcharge

If its the old style alternator one of the fields is grounded or maybe one of the fields on the alternator has a bad isolator on a brush screw. With both field wires disconnected check if they are going to ground with a meter & car not running

Happened to me and the culprit was the plastic isolator on the alternator's power terminal. It failed and was grounding itself out on the housing.

Sounds like the alternator is at maximum output.

It will charge wide open if the green field wire or lug is going to ground which is how the voltage regulator works by variable resistance to ground,

I did have a regulator that would charge wide open one time also

Replaced both alt and reg with OE stock. I also ran amp test on fuel pump 3 amp and replaced and grounded every thing I could get to even the starter I will update in next couple days

Well as of now changed out alt and reg { Might as well be a part changer besides I have the stuff in stock} I rewired the field wire with heavier gauge wiring . I'll let you know {weather stinks } Thanks for help folks!

That happened to me as well burned all the way up the column. Brand new alternator must have been a return that someone messed with before I got it. Field terminal was grounding on the housing I think.

Same thing here , melted the wires right up the the ammeter , bare wires eventually were shorting out under the dash.