I have been installing Fire Alarms in Dollar stores lately and as part of the install I must also use Duct detectors.for smoke control and in hooking these units up I have been finding sevral issues with HVAC installers.I hold a HVAC reclaim liscense type II and III

Issue 1# the secondary 24 volt side of the control transformer is suppose to be interuppted by the detectors relay which stops smoke from moving thru the duct work. This involves running a brown 18/2 thermostat wire down from roof unit to the duct detector but in the last few units I have worked on I have found that instead of the 24 volt secondary side being used they have tapped the 18/2 -50 volt rated thermostat wire into the 230 volt side of the transformer to the duct detector needless to say the danger to me the alarm tech and fact this wire will eventually break down and cause problems including a fire. Where i find this i fix it and report to AHJ and HVAC contractor.

Issue 2# when roof units are shipped they put wooden blocks between the compressor and piping to protect it during shipping these blocks are to be removed after unit is placed on roof and made ready but several times i have found them still in place.again a phone call to AHJ and contractor.

Issue 3#
when a roof top unit is hooked to 230 volts 3 phase many name plates say (fuse only )which means a breaker alone can not protect the unit a fused disconnect with proper rated fuses must be used to handle the short circuit rating of the
compressor. many times i see this totally ignored and the unit is protected only by a breaker which again can lead to a fire .

4th Issue
I see HVAC units replaced and old undersized or over sized feeds being used and not properly rated fuses or breakers being used.to match the install.

5th isssue
Wrong wiring being used to units indoor romex instead of sunlight rated UF or PVC or steel conduit as codes dictate plus undersized conductors and often times no or undersized grounds.

6th Issuue
units are not wired for proper voltage comming into facility a unit designed for 120/208 3 phase 4 wire Y configuration left in the 3 phase 230 Delta configuration and vis versa which can burn out compressors and controls.

There apears to be a total lack and understanding of NEC 70 as it goes with HVAC techs I have even heard instructors at courses I have attended say HVAC does not need to follow NEC 70 at which point i identify myself in class and put the instructor on notice as well as his employer he has given improper information to the class.
Is it me or are there just too many HVAC contractors out there who do not give a dam or care to follow any code and is code enforcement lacking as well or does the AHJ just not know to look for these problems or does not care to.
Thoughts??