Emergency Disconnect Requirement Calculator
Check the NEC 230.85 emergency disconnect rules for a one- or two-family dwelling: whether a disconnect is required, where it has to go (a readily accessible outdoor location), when multiple disconnects must be grouped, and the exact marking label for a service, meter, or other supply-side disconnect. Pick the type and the tool states the label; add the location and count and it returns a compliance verdict.
How to use this calculator
- Pick the occupancy. 230.85 applies only to one- and two-family dwellings; for any other occupancy the tool points you to the Service Disconnect rules.
- Pick the disconnect type (service, meter, or other supply-side) and read the exact marking label it must carry.
- Optionally say whether the disconnect is in a readily accessible outdoor location and how many emergency disconnects are provided.
- If more than one is provided, say whether they are grouped.
- Read the verdict: meets 230.85, does not meet 230.85, or needs review when a condition still has to be confirmed.
NEC reference
This calculator implements NEC 2020 230.85, Emergency Disconnects. For one- and two-family dwelling units, all service conductors shall terminate in disconnecting means having a short-circuit current rating equal to or greater than the available fault current, installed in a readily accessible outdoor location; where more than one disconnect is provided, they shall be grouped; and each disconnect shall be marked, per 110.21(B), as a service disconnect, a meter disconnect installed under 230.82(3), or another listed supply-side disconnect suitable for use as service equipment. The term "readily accessible" uses the NEC Article 100 definition. NEC 2020 is the site default; the 2023 and 2026 changes are summarized below.
Results are for reference only. Verify against the applicable adopted edition of the NEC and consult a licensed electrician for code compliance.
What 230.85 requires, in order
Section 230.85 was new in the 2020 NEC. Its purpose is to give fire and rescue crews a way to cut power to a home from outside, without entering the building or opening the service panel. Four things have to be true for a one- or two-family dwelling.
| Requirement | What it means | Source |
|---|---|---|
| Applies to one/two-family | All service conductors terminate in the disconnecting means; the rule is specific to one- and two-family dwelling units | 230.85 |
| Readily accessible, outdoor | Reachable quickly without obstacles or a ladder, located outside the dwelling | 230.85 + Article 100 |
| Grouped if more than one | Two to six disconnects must be grouped in one location | 230.85 |
| Marked by type | One of three labels, permanent and legible per 110.21(B) | 230.85(1)-(3) |
The three marking labels
The label depends on what the disconnect is. The marking tells a responder whether the device they are about to operate is the service equipment, a meter disconnect, or something else on the supply side.
| Disconnect | Marking | Source |
|---|---|---|
| Service disconnect | EMERGENCY DISCONNECT, SERVICE DISCONNECT | 230.85(1) |
| Meter disconnect (per 230.82(3)) | EMERGENCY DISCONNECT, METER DISCONNECT, NOT SERVICE EQUIPMENT | 230.85(2) |
| Other supply-side disconnect suitable for service use | EMERGENCY DISCONNECT, NOT SERVICE EQUIPMENT | 230.85(3) |
Short-circuit current rating, not computed here
230.85 also requires the disconnecting means to have a short-circuit current rating equal to or greater than the available fault current at its location. That is a function of the serving utility transformer and the service conductors, and it comes from a fault-current study, not from this tool. This calculator flags the requirement but does not compute available fault current or compare it to a device rating.
How the editions differ
This tool models the 2020 NEC, the site default and the edition most widely adopted across US jurisdictions. Two later changes are worth knowing. The 2023 NEC revised 230.85 so the disconnect must be on or within sight of the dwelling unit, where within sight means visible and not more than 50 ft distant, and it reworded the third marking case. The 2026 NEC deleted 230.85 as its own section and folded the outdoor emergency-disconnect requirement into 230.70, where the service disconnect itself serves as the emergency disconnect. Always check which edition your jurisdiction has adopted.
Worked examples
A single-family house has one service disconnect in a meter-main combination mounted outside, reachable without a ladder. That is one disconnect in a readily accessible outdoor location, so it meets 230.85, and it is marked EMERGENCY DISCONNECT, SERVICE DISCONNECT.
A two-family dwelling is fed through an outdoor meter disconnect ahead of two separate service disconnects for the two units. Because more than one disconnect is provided, they must be grouped. The meter disconnect carries EMERGENCY DISCONNECT, METER DISCONNECT, NOT SERVICE EQUIPMENT, and each service disconnect carries EMERGENCY DISCONNECT, SERVICE DISCONNECT. If those disconnects were scattered rather than grouped, the installation would not comply.
Common mistakes
- Putting the disconnect indoors. 230.85 requires a readily accessible outdoor location, not an indoor panel in a basement or garage.
- Leaving multiple disconnects scattered. Two to six emergency disconnects must be grouped in one place.
- Using the wrong label. A meter disconnect is not marked the same as a service disconnect; the label has to match what the device actually is.
- Assuming it must be the service disconnect. The emergency disconnect can be a separate device that provides no overcurrent protection.
- Applying it to a commercial building. 230.85 is a one/two-family rule; other occupancies follow 230.70 and 230.71.
Frequently asked questions
When is an emergency disconnect required?
Under the 2020 NEC 230.85, for one- and two-family dwelling units. All service conductors must terminate in disconnecting means in a readily accessible outdoor location. It does not apply to other occupancies, and only in jurisdictions on the 2020 NEC or later.
Where does it have to be located?
In a readily accessible outdoor location (2020). Readily accessible means reachable quickly without obstacles or a portable ladder. The 2023 NEC changed this to on or within sight (within 50 ft) of the dwelling.
What marking does it need?
One of three labels, permanent and legible per 110.21(B): EMERGENCY DISCONNECT, SERVICE DISCONNECT for a service disconnect; EMERGENCY DISCONNECT, METER DISCONNECT, NOT SERVICE EQUIPMENT for a meter disconnect; or EMERGENCY DISCONNECT, NOT SERVICE EQUIPMENT for another supply-side disconnect.
Do multiple disconnects have to be grouped?
Yes. Where more than one emergency disconnect is provided, 230.85 requires them to be grouped in one location.
Does it have to be the service disconnect?
No. It can be a separate disconnect that provides no overcurrent protection, so long as it has a short-circuit current rating at least equal to the available fault current and carries the right marking.
Related calculators
- Service Disconnect Number & Rating Calculator: how many service disconnects the NEC allows and their minimum rating per 230.71 and 230.79.
- Service Size Calculator: size service-entrance conductors and the grounding electrode conductor from a known load.
- Overhead Conductor Clearance Calculator: minimum vertical clearance of an overhead service drop per NEC 230.24.
- Working Space Clearance Calculator: required depth, width, and headroom in front of the service equipment per NEC 110.26(A).
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