Rooftop heat pumps

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JDB3

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San Antonio, Texas
An HVAC friend of mine, who is doing an "Eye Clinic", is running into trouble withe the electricians.
First off, they did not figure heat pumps into their load calculations, said that it would be an extra charge to the HVAC contractor to accommodate them. They are now complaining that they have no terminal blocks to terminate their wires for the roof top package units.
They are also saying that the duct work (which the inspector passed) was not done according to code.
I am an master electrician, have ran an electrical shop with up to 60 employees, have my own electrical contracting license / business.
I feel that the electricians under bid the job, even though there have been many electrical changes/extras that could have made up for their bidding problem.
The roof top units have wires to connect to for the back-up heat strips & the blower motor. The electricians just want to mount a disconnect to the unit & run one set of wires to terminal blocks. They argue that wire nuts should not be used to connect their wires to the wires inside the unit.
Is there such a fuse block that takes a set of 3 wires to feed it & the fuse block with 2 different sizes of fuses (3 for the heat & 3 for the motor)?
The HVAC friend had just called me about this, & it is past this old timer's bed time. Thanks
 
I think you mean heat strips and not heat pump?

What they’re likely saying is the terminal block inside the RTU won’t accommodate two conductors per lug to go hit the strips, which are likely installed in the plenum.

I missed this once too on quite a few units and just ate the Polaris lugs I needed to provide the additional tap. It was a lesson in taking time to lookup every model specified in the schedule and understanding what type of heat strip would be provided. The electrical schedule will typically not provide that information.

If the RTU model #’s were in the plans, and listed accessory strips, then it’s on the electrician to provide whatever necessary to connect them.

Edit…. The strips may not necessarily be in the plenum but they still would have a separate wiring enclosure within the RTU that you have to take another set of conductors to for power. Some of them I’ve wired have a tap block for multiple conductors where you can hit the strips first, then tap off for heat and power to the controls and blower/compressor.

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A wise man once said, "The big print giveth and the fine print taketh away.". If the units are in the bid documents, too bad for the person who missed it.
 
The architect, on this job did not check with the local codes to begin with. This jurisdiction limits 10 openings per circuit (receptacles or lighting). The electrician on the job stated that he had to re-design circuits to allow for this & for the additional lighting added (bunch).
I do nor know what the original specs called for as to the HVAC system, but it turned out to be 4 roof top units (heat pumps) with 16 zones (individual thermostats ). I did not see the final wiring for the fixtures, but they used MC cable with a lot of slack in it & little strapping/securing the cable. Parts of the wiring was OK, some was very sloppy!
 
Sound like time to get the GC involved. I have seen this before where one trade is ask to do a bid based on X and the other trade the same.
If bids were to the owner and no GC they both may be doing what they bid. If no one did a review then that is what you get. At some point an AHJ will write a correction notice and some one will get a change order. I always had a clause to cover just this. I would think an eye clinic would have a GC and permits pulled. I am working on a project where the whole HVAC package changed due to availability. It was brought to the attention to the GC via an RFI and change order. I take it there no engineered plans for this project.
Did anybody ask if the electrician had load info prior to calculations preformed. Many times I was told tonnage for prelim price and calcs.
As far as roof top units go we hit a disc and wire into a single point inside unit or factory supplied disc. everything else is factory supplied with unit.
As far as the wire nuts go if the unit wiring diagram says wire to leads than wire nuts it is. must be very small units.
When heat strip kits are installed it usually comes with a factory install kit which is has to be installed by the licensed HVAC contractor. It part of there equipment. As far as duct work goes not our scope of work and not our problem as an electrical contractor.

Defiantly sound like a lack of communication some where.

to answer your last question, YES. Usually found inside the supplied equipment.
Also they use a set of mini circuit as well on a din rail.
 
brantmacga said:
that might be the dumbest thing I've ever heard.
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Welcome to Tulsa. There wording is outlet. Not recpt.
its violated every day. When i first got here and was told that I ask how do you wire for lighting in a building. They said you stupid or something.
I replied stupid is stupid does.
Tulsa amendment, Title 52 chapter two electrical code.
210.19 (A) (4) Other Loads - Amendatory. Branch-circuit conductors that supply loads other than those specified in 210.2 and other than cooking appliances as covered in 210.19 (A)(3) shall have an ampacity sufficient for the loads served and shall not be smaller than 14 AWG. 20 ampere general-purpose branch circuits for dwellings shall supply a maximum of 10 outlets, 15 ampere general-purpose branch circuits for dwellings shall supply a maximum of 8 outlets. 20 ampere general-purpose branch circuits for other than dwellings shall supply a maximum of 8 outlets.

I know what they meant and still find it interesting.

Outlet. A point on the wiring system at which current is taken
to supply utilization equipment.

Utilization Equipment. Equipment that utilizes electric energy
for electronic, electromechanical, chemical, heating, lighting,
or similar purposes.

I laugh almost every day.

Many here struggle to pass the test. Something as simple as 180 va general use they use 20/8. They can not find 8 on the test.
 
This must be a package heat pump with emergency heat. Per most manufacturers they require two separate dedicated circuits and two disconnects.
 
You have to follow the nameplate on the HVAC Units (heat Pumps) for information on how to wire this.

The manufacturer will provide MOCP and MCA information to size the wire and the circuit protection.

As @mtnelect mentioned some manufactures allow this with one feed, some want two and some give you the option
 
Tulsa Electrician said:
Sound like time to get the GC involved. I have seen this before where one trade is ask to do a bid based on X and the other trade the same.
If bids were to the owner and no GC they both may be doing what they bid. If no one did a review then that is what you get. At some point an AHJ will write a correction notice and some one will get a change order. I always had a clause to cover just this. I would think an eye clinic would have a GC and permits pulled. I am working on a project where the whole HVAC package changed due to availability. It was brought to the attention to the GC via an RFI and change order. I take it there no engineered plans for this project.
Did anybody ask if the electrician had load info prior to calculations preformed. Many times I was told tonnage for prelim price and calcs.
As far as roof top units go we hit a disc and wire into a single point inside unit or factory supplied disc. everything else is factory supplied with unit.
As far as the wire nuts go if the unit wiring diagram says wire to leads than wire nuts it is. must be very small units.
When heat strip kits are installed it usually comes with a factory install kit which is has to be installed by the licensed HVAC contractor. It part of there equipment. As far as duct work goes not our scope of work and not our problem as an electrical contractor.

Defiantly sound like a lack of communication some where.

to answer your last question, YES. Usually found inside the supplied equipment.
Also they use a set of mini circuit as well on a din rail.
Click to expand...
The HVAC contractor is a friend of the owner & knew that a zoned system would be a better application in this case & would save money using heat pumps. The architect did not listen to what was wanted/needed. He also showed a line drawing of lighting & receptacles that exceeded the number of openings that this AHJ allows. The on-site electrician even said that he had to re-design the circuits. Apparently the GC has used this electrical company before, whereas this is the first time for this HVAC company. I rather doubt that there was any communication as to the HVAC equipment that was to be used. The roof-top units a 3 & 5 ton units & 2 units just came with pigtails for the internal wiring. HVAC guy did not install one set of back-up heat strips because the electrical contractor threatened to make "him" pay for the additional cost (since they were not figured into load calculation). Who to blame? Toss up!
 
If this job was planned and drawn by an engineer, it is on him/her/it and the owner. (LOL). If it was designed by the electrical contractor, it is on them for not doing due diligence (unless the HVAC contractor failed to disclose the proper specs) As far as connections go, unless it’s something really off the wall, the EC should already have money in there for that. If that job was bid that close, they do not need to be in the contracting business.
 
If the project is located in a usually cold climate ... whoever will eventually occupy the structure will be disappointed because most package Heat Pumps will heat down to 50 degrees without emergency heat. But if it gets colder someone will have to pull a new circuit for it eventually !
 
It is quite common here for specs to require a single point connection for HVAC Units. Contrary to others here, I would tend to finding a way for my fellow electrician to recover extra cost. This was apparently a design build since the OP said the electrician didn’t figure heat strips in to the calculations. So how did he arrive at the hvac ampacities? Unless the hvac plans specified a heat pump, he would have no reason to assume one would be provided.
 
This is another example of how bidding can be a disaster for the average contractor. On large projects you have a Resolution Committee made up of representatives of all the trades that will resolve conflicts in a fair manner. On small projects there is none, one mistake and you are "toast".
 
Strathead said:
It is quite common here for specs to require a single point connection for HVAC Units. Contrary to others here, I would tend to finding a way for my fellow electrician to recover extra cost. This was apparently a design build since the OP said the electrician didn’t figure heat strips in to the calculations. So how did he arrive at the hvac ampacities? Unless the hvac plans specified a heat pump, he would have no reason to assume one would be provided.
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The HVAC contractor gave him the ampacity of the units.
 
mtnelect said:
If the project is located in a usually cold climate ... whoever will eventually occupy the structure will be disappointed because most package Heat Pumps will heat down to 50 degrees without emergency heat. But if it gets colder someone will have to pull a new circuit for it eventually !
Click to expand...
Nope, it is in South Central Texas. Vast majority of days in May were above average, high 80s to upper 90s.
 
Strathead said:
It is quite common here for specs to require a single point connection for HVAC Units. Contrary to others here, I would tend to finding a way for my fellow electrician to recover extra cost. This was apparently a design build since the OP said the electrician didn’t figure heat strips in to the calculations. So how did he arrive at the hvac ampacities? Unless the hvac plans specified a heat pump, he would have no reason to assume one would be provided.
Click to expand...
The HVAC guy told others contractors (at a round table discussion before job started) , that a Heat Pump system was what he was bidding, to help save the Owner money when heat was needed. Last year we had an exceptionally cold week (from 8 to 30 degrees). Many people did not have power for 3 straight days
 
The electrician is saying that the HVAC contractor is responsible for supplying "Ilsco" type connectors (around $200 cost). The wiring for the unit shows wire nuts for the connections. I am go to take some wire nuts there tomorrow & ask why not use these! If they balk, I think that the electrician should bear the cost.
 
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