They have a 50amp breaker and ran #6 up into a box spliced it with split bolts to #4 teck cable for the length of run then into another box spliced it again to a #6 for a drop to a machine.I know you can run #4 to #6 as long as the breaker is sized for #6 but doing it at both ends seems just plain wrong since Ive never seen this done before with ten yrs in the trade.They also used BX connectors instead teck connectors???Someone else did the work and they want me to terminate it.I will be inspected and they say i will pass but i don't think so.
opinions please
thanks

I don't see a prob with the wire sizing.
Only need the teck connectors if it's outside or in a damp location. Had this come up recently where one inspector said yes, the other said no. Final answer was that if it's inside you treat it like bx. Just strip back enough of the outer casing so the connector is in contact with the metal sheath.

First teck connectors are required for wet locations or hazardous locations. Flex and BX connectors are approved for dry locations for teck assuming condition 1 and 2 do not exist. The biggest challenge with many of the dry connectors is that they do not tighten up to the armour thus neither a good mechanical or electrical connection.
Now #4 to #6. as long as the wire is that size for voltage drop and the OC protection is for #6 then great. Maybe the largest lugs in the supply and load would not accomodate #4 wires. I saw a job that sized all the home runs for %3 volt drop and a few receptacle runs used #6 which were spliced down to #12 for connection to breakers and receptacles. I think that job was designed by some guy that just took a harmonics and volt drop seminar. They might even recoup the added expense over a hundred years on line loss savings ;-) By the way it was an OSH (Worksafe) office in Vicoria BC.

EddyCurrent,mikesh
Ok thanks for the replies