Cross-trade conflicts.
A cross-trade conflict is a submittal that matches its own trade's drawings and spec but doesn't fit another trade's work. The most common kind is electrical: a rooftop unit, a pump or a kitchen appliance submitted at a voltage, phase or amperage the circuit feeding it was never designed for. Each package passes its own review, because each reviewer reads only their own drawings. The conflict shows up when the equipment arrives.
Why they slip through
Each trade's package goes to a different reviewer, often a different consultant, weeks apart. The mechanical engineer checks the rooftop unit against the mechanical schedule. The electrical engineer checks the panelboards against the panel schedules. Nobody is assigned to read the rooftop unit's electrical data against the panel that feeds it, so a mismatch can be approved twice and caught by neither review.
The contract usually puts that coordination on the contractor. Under AIA A201-2017, section 3.12.6, submitting a shop drawing or product data means the contractor represents that it has checked and coordinated the submittal with the requirements of the work. In practice, that check is the one most often skipped.
What it costs when it isn't caught
Two stories from the contractor and engineer forums we read this fall show the stakes. An engineer described fire and smoke dampers approved by the mechanical team at 230 V when the electrical design ran 120 V to them, with the actuators on 1,200 installed dampers needing replacement. A contractor described a change order after rooftop units, pumps and boilers were scheduled, submitted and bought as 230 V single-phase while the electrical work was run at 460 V three-phase. Neither was a hard catch. Both were a line on a data sheet that nobody read against the panel schedule.
Where conflicts hide
- 1Voltage and phase. The equipment's nameplate voltage and phase against the panel and circuit that feed it.
- 2Amps and protection. Full-load amps, minimum circuit ampacity and maximum overcurrent protection against the breaker or fuse on the panel schedule.
- 3Disconnects and starters. Who furnishes them, and whether their rating matches the equipment.
- 4Connections. Water, gas and drain sizes against the plumbing drawings; duct and curb sizes against the mechanical and structural drawings.
What we found on one job
On our sample project, a restaurant fit-out, we read every piece of mechanical and kitchen equipment against the circuit that feeds it. We found five conflicts. The worst was the rooftop units, submitted at 460 V three-phase for a building served at 120/208 V, which had already been approved when the check found them. On the kitchen side, the equipment schedule and the panel schedule disagreed on the circuits for a combi oven (150 A against 175 A), a conveyor dishwasher (60 A against 150 A), the undercounter dishwashers and a chef's station. Each one is a different selection on paper, and a new unit or new wiring in the field.
How to catch them
- 1Pair every piece of equipment with its circuit. Tag on the equipment schedule, circuit on the panel schedule. The pairing is the check.
- 2Read the submitted sheet, not the schedule. The schedule may agree with the panel while the product actually submitted doesn't.
- 3Mind the order. The trade that submits second gets checked against what's already approved. Drawings that disagree with each other get both sides flagged, and the question goes to the designer.
- 4Write it so someone can act. Name both items, both sheets and the two values, so the designer or the coordinator can settle it in one reply.
The electrical submittals guide covers the panel side of the same check.
How Beem handles it
Our cross-trade check, in beta, pairs each piece of equipment with the circuit that feeds it across every package on the job. It flags only the conflicts it can show on both sheets, marks both rows when the drawings disagree, and drafts a note for the designer or coordinator. Our trade experts look over every flag, and the decision stays with the reviewer.
Questions people ask
What is a cross-trade conflict in a submittal?
A submittal that matches its own trade's drawings and spec but doesn't fit another trade's work, most often a piece of mechanical, plumbing or kitchen equipment whose voltage, phase or amperage doesn't match the electrical circuit designed to feed it.
Who is responsible for coordinating submittals between trades?
Under AIA A201-2017, section 3.12.6, the contractor represents that it has checked and coordinated each submittal with the requirements of the work. The design team's review checks general conformance. Check your own contract, since terms vary.
What are the most common cross-trade conflicts?
Electrical data on other trades' equipment: voltage and phase, full-load amps and the breaker size, and who furnishes disconnects and starters. Connection sizes for water, gas, drains, ducts and curbs come next.
How do I catch a voltage mismatch before it is installed?
Pair every piece of equipment with the circuit that feeds it, then read the submitted data sheet against the panel schedule: voltage, phase, amps and overcurrent protection. Do it when the second trade's package arrives, not at startup.
Does Beem check across trades?
Yes, in beta. Beem pairs each piece of equipment with its feeding circuit across the job's packages and flags conflicts it can show on both sheets, with a note for the designer. Our trade experts look over each flag, and the reviewer decides.