FAC-003 has gone through five versions since 2007, and FAC-003-5 is the current one. This page walks through what NERC's own version history records for each version, and what to recheck if your program still refers to an older one. It is a summary of the version history, not a redline. For line-by-line differences, use the redlines and implementation plans for each version on NERC's standards page.
Version timeline
| Version | Approved or adopted | What NERC's version history records |
|---|---|---|
| FAC-003-1 | Regulatory approval, April 4, 2007 | Effective date of the first version |
| FAC-003-2 | Adopted by the NERC Board November 3, 2011. FERC Order No. 777, March 21, 2013 | FERC approved it and directed NERC to run testing to get empirical data on flashover distances |
| FAC-003-3 | Adopted May 9, 2013. FERC approved September 19, 2013 | Enforceable July 1, 2014 for Transmission Owners. For Generator Owners, R3 became enforceable January 1, 2015 and the other requirements January 1, 2016 |
| FAC-003-4 | Adopted February 11, 2016. FERC approved April 26, 2016 | Adjusted the AC values in Table 2 (MVCD), based on the empirical flashover testing FERC asked for |
| FAC-003-5 | Adopted May 13, 2021. FERC approved March 4, 2022 | Listed as "Revisions." ReliabilityFirst lists April 1, 2024 as its effective date |
FAC-003-3 to FAC-003-4: the clearance table
The change NERC records for FAC-003-4 is to Table 2, the Minimum Vegetation Clearance Distances (MVCD) for AC lines. FERC's Order No. 777 directed NERC to gather test data on flashover distances between conductors and vegetation. The results were filed with FERC in August 2015 and used to adjust the table. A note in Table 2 says a change in transient overvoltage factors is what drove the decrease in MVCD at 345 kV and above.
If your procedures, work instructions or clearance tables still cite MVCD values from FAC-003-3, check them against the current Table 2. The distances you keep in practice can be larger than the minimum. The standard itself says good maintenance practice achieves substantially greater distances.
FAC-003-4 to FAC-003-5: scope wording
The version history lists FAC-003-5 as "Revisions" and does not summarize them. What the FAC-003-5 text says about lines below 200 kV: they are covered if the Planning Coordinator or Transmission Planner has identified them, in its Planning Assessment, as a Facility whose loss or degradation is expected to cause instability, Cascading or uncontrolled separation, or if they are elements of a Major WECC Transfer Path. If you built a scope list against older wording, recheck it against the current text.
What the current version requires
See our FAC-003-4 and FAC-003-5 clearance guide for the requirements (R1 to R7), the full Table 2 excerpt, and the examples of evidence the standard lists. Those examples, such as dated work orders, dated invoices and dated inspection records, are examples and not a required format.
Where LineGuard fits
LineGuard AI produces a dated satellite screening report for a line file, ranked by how much green vegetation sits in the corridor you set. It does not measure clearance distances and it does not determine compliance. Whether a screening satisfies a requirement for a given line is up to the registered entity and its Regional Entity.
Sources: NERC FAC-003-5 version history and Table 2 notes. ReliabilityFirst, Enforcement Explained: Trends in vegetation management.