Chart
Current-limiting fuse let-through vs SCCR chart
Visualize how current-limiting fuses can reduce downstream peak current and I2t exposure for equipment SCCR review.
Chart boundary
Does not select a fuse, raise equipment SCCR, approve a control panel, or replace manufacturer combination ratings.
let through curve
Available fault current to let-through band
The curve concept shows why two devices with the same ampere rating can create different downstream stress.
Scopeprotection and fault currentX-axisprospective RMS fault current kAY-axispeak / apparent let-throughReviewAnnualNextAvailable fault current margin calculator
Fuse classJ / CC / RK / L
Class and amp rating change the band.
Prospective currentsystem available kA
Use calculated or utility-provided fault current.
Let-throughpeak and I2t
Use manufacturer charts, not generic values.
SCCRlisted combination required
A fuse alone does not relabel equipment.
Decision reference
Show the relationship between available fault current, let-through current, and downstream equipment SCCR questions.
| Curve band | What it shows | Risk cue | Handoff |
|---|---|---|---|
| Prospective current | Unlimited available current level | Can exceed equipment rating | Fault-current margin calculator |
| Peak let-through | Current-limiting peak stress | Must use manufacturer chart | Fuse data sheet |
| I2t let-through | Thermal energy stress | Combination rating needed | SCCR guide |
| Downstream SCCR | Equipment withstand context | Label and listing govern | AIC/SCCR label table |
Use notes
- Use this chart as a planning and conversation aid only.
- Confirm current utility requirements, product markings, manufacturer instructions, and local authority requirements before field work.
- Use the linked calculator or table when the task needs project-specific arithmetic.
Reference sources
Open the underlying public references before treating the chart as project guidance.