Service · fault duty · selectivity
Short circuit coordination study that stops one fault from tripping the plant
US arc flash studies, PE-reviewed, quoted in 24 hours. Fault duty and device settings checked in the same model.
- PE-reviewed
- Built on current NFPA 70E-2027
- IEEE 1584-2018
- Field engineers travel to every US state
- Written quote in 24 hours
A short circuit coordination study is the engineering check that calculates the fault current available at every bus, confirms each breaker and fuse can interrupt it, and sets protective devices so only the one closest to a fault opens. AFSC delivers it PE-reviewed, with settings your electricians can apply, and quotes it within 24 hours.
Why now
Triggers that call for new settings
A trip took down more than it should
When a branch fault opens the main, coordination failed. The study shows which setting caused it and what to change.
The utility raised available fault current
Higher fault current can push breakers past their interrupting rating. That is an equipment failure waiting for a fault.
New load or a new transformer
Every added source or feeder shifts fault levels and clearing times downstream. Settings tuned for the old system drift out of step.
What you get
| Deliverable | Detail |
|---|---|
| Fault current at every bus | Three-phase and single-line-to-ground values in kA |
| Equipment duty evaluation | Interrupting and withstand ratings compared with available fault current, per NEC (NFPA 70) 110.9 and 110.10 |
| Time-current curves | Coordination plots for each protective path from source to load |
| Recommended settings | Pickup and delay settings in A and s, ready for your electricians |
| Selective coordination check | Required systems checked: emergency, legally required standby, critical operations power |
| PE-reviewed report | Findings ranked by risk with the change that fixes each one |
How the study runs
Gather the data
Utility fault data, transformer nameplates, cable runs and every breaker and relay setting in scope.
Model the system
A single model holds sources, impedances and devices, verified against the gear on site.
Check and coordinate
Duty ratings first, then time-current curves, adjusted until each fault clears at the right device.
Report and settings sheet
PE review, the report, and a settings sheet your team or ours can apply.
One nuisance trip costs more than the study
Send the one-line diagram and your trip history. We return scope, a fixed price and a dated plan within one business day.
Codes and standards applied
| Reference | What it covers |
|---|---|
| NEC (NFPA 70) 110.9, 110.10 | Interrupting ratings and short-circuit current ratings |
| NEC (NFPA 70) 700.32, 701.32 | Selective coordination for emergency and legally required standby systems |
| NEC (NFPA 70) 708.54 | Selective coordination for critical operations power systems |
| IEEE 1584-2018 | Incident energy from the same model, when you add the arc flash scope |
Short circuit study, the first check
A short circuit study finds the maximum fault current each bus can deliver and compares it with the rating of every breaker, fuse and panel on that bus. If the fault is larger than the rating, the device can fail violently instead of interrupting. This check comes first because it protects the equipment itself.
Protective device coordination study, the second check
A protective device coordination study sets breakers, fuses and relays so the device nearest a fault opens first and everything upstream stays closed. The result is a fault that isolates one feeder instead of a whole building. Good coordination also feeds the arc flash numbers, because clearing time drives incident energy.
Coordination study, electrical basics for plant teams
Think of coordination as a queue. Each protective device waits its turn, and the one closest to the fault goes first. Engineers prove the queue holds by plotting time-current curves for every path. Where two curves overlap, a fault could open both devices, and the study changes a setting to separate them.
Related services, tools and guides
Frequently asked questions
Question not here? Ask an engineer
When is an electrical coordination study required?
An electrical coordination study is required when the NEC calls for selective coordination, such as emergency, legally required standby and critical operations power systems. It is also needed when you add sources or major loads, change the utility service, see nuisance trips, or need clearing times for an arc flash analysis.
How often should settings be reviewed?
Review settings whenever the system changes and at least alongside your 5-year arc flash review. Utility upgrades, new transformers and added motors all shift fault levels. Reviewing both studies together costs less than running them separately, because one verified model serves both sets of calculations.
Will you change the breaker settings for us?
Yes. We deliver a settings sheet your electricians can apply, and our field engineers can apply the settings during a planned outage if you prefer. Either way, the as-left settings go back into the model, so the report, the curves and the labels all match the equipment in front of you.
Can you show an example of a coordination study?
Yes. Request the sample report and you will see the time-current curves, the duty table and the settings sheet in the format we deliver. It shows exactly what your team receives, before you commit to anything, and it is sent by email within one business day of your request.
What does the study cost?
Cost tracks the number of buses and devices in scope, the voltage levels, and whether settings data is on file. Send your one-line diagram and we return a fixed written price within 24 hours. Adding the arc flash scope to the same model costs less than buying it later.
Does this study need an outage?
Usually not. Nameplate and setting data can be read with equipment energized where that is safe, by engineers wearing the right PPE. Applying new settings typically needs a short, planned outage per device, which we schedule with your operations team well ahead of time.
Get your arc flash study quoted
Tell us about your facility. An engineer replies within one business day with scope, timeline and price.
- IEEE 1584-2018 and NFPA 70E-2027, PE-reviewed
- Labels and training in the same scope
- Field engineers travel to any US state