MG Car Repair: Battery connection 78 MGB, dc generator, battery connection

Question
QUESTION: My Grandson ripped the old battery out before I had a chance to looked to see how the post line up. I put the new battery in and the alternator started to smoke. Is the '78 MGB a positive ground?

ANSWER: Hi Larry,
All MGs that have an alternator are negative ground. Older MGs with a DC generator can have it either way if they first polarize the generator that way and make other changes.

Your car is Negative ground. If you connected it up positive ground it would melt down the 12 ga wire to the alternator and also melt down the alternator itself too.
Howard

---------- FOLLOW-UP ----------

QUESTION: I very much appreciate your quick response. I was almost sure we got it right the first time but is there another reason the alternator would smoke? Thanks in advance.

Answer
If the alternator was already fried before you replaced the battery then putting in the new battery had nothing to do with it, other than letting more smoke out.

However, if you touched the cables backwards that would fry the diode pack in the alternator. Usually when you connect a battery up backwards there are some sparks at the cable ends when you try to connect them up.

Howard