The
Jean Muller KETO-1-2/F is the size 1 NH fuse-switch-disconnector body from the KETO range, engineered for
high-current DC isolation in solar PV and battery energy storage systems (BESS). This is the
bare switch body only — it accepts a pair of customer-selected NH1 fuse-links (sold separately, see 160A and 200A variants) sized to match the battery or inverter circuit's maximum current. Rated to
250A continuous and built for
baseplate mounting with heavy-duty M10 flat terminals, the KETO-1-2/F provides a visible, lockable air-gap disconnect point between battery banks and inverters, satisfying the isolation and fused-protection requirements of most DC-coupled storage installations.
250A
Max Rated Current Ie
⚠ Fuse-links not included
This is the KETO-1-2/F switch body only (article T100112002) — it does not ship with NH1 fuse-links fitted. Two matching NH1 fuse-links must be ordered separately and sized to the installation's maximum DC current with an appropriate safety margin, per the system designer's calculations. See our KETO-1 160A and 200A pre-fused variants if you'd prefer a fuse-link pair included.
◆ Voltage rating: manufacturer datasheet vs. distributor listings
Several UK and international resellers list this product at 690V DC. Jean Müller's own published datasheet for the KETO-1-2/F (article T100112002) instead specifies a rated operating voltage Ue of 250V and a utilisation category of DC-22B (250V/250A), with an 8kV rated impulse withstand voltage. We have used the manufacturer's own datasheet figure here. If your design assumes 690V DC operation, please verify directly against the switch's DIN EN 60947-3 rating plate or contact Jean Müller before specifying.
ℹ Fuse monitoring not fitted as standard
The base KETO-1-2/F body has no fuse-blown indication or monitoring contact fitted. Fuse-status indication relies on the visual indicator built into compatible NH1 fuse-links, or a separately-specified KETO fuse-monitoring accessory if remote signalling is required.
Uniform KETO Platform Design
Shares its cover cut-out and touch-protection components with every other KETO frame size (000 to 3), so panel builders can standardise enclosure cut-outs across a mixed-size fuse-switch installation.
Reversible DIN Rail Adaptation
The mounting adaptor reverses to suit both 5mm and 10mm DIN rail thicknesses, and the cable outlet can be converted from bottom to top exit without additional parts.
Touch-Safe Fuse Handling
IP20C degree of protection with the front cover and lateral shrouds fitted means live NH1 fuse-links can be inserted, removed, and inspected without exposing installers to live blades.
High Short-Circuit Withstand
Rated conditional short-circuit current Icc of 35kA at 250V DC, giving the switch body the mechanical and thermal robustness to survive a downstream fault event without damage to the housing.
Wide Operating Temperature Range
Functions from -25°C to +70°C (current derating applies above standard ambient), suitable for plant rooms, outbuildings, and unheated enclosures housing battery inverters.
Low-Loss Silver-Plated Contacts
Silver-plated, independently sprung fuse-clip contacts (E-Cu, versilbert, fremdbefedert) keep total power dissipation at rated current to just 10W, minimising heat build-up in enclosed battery cabinets.
| Electrical Ratings |
| Rated operating voltage Ue |
250V |
| Rated operating current Ie |
250A |
| Conventional free-air thermal current (with fuse-links) Ith |
250A |
| Conventional free-air thermal current (solid links) |
350A |
| Rated isolation voltage Ui |
1,000V |
| Rated impulse withstand voltage Uimp |
8kV |
| Rated conditional short-circuit current Icc |
35kA (DC 250V) |
| Utilisation category |
DC-22B (250V / 250A) |
| Total power loss at Ith (without fuse-link) |
10W |
| Max. permissible power dissipation per fuse-link |
23W |
| Power loss at 80% Ith (without fuse-link) |
6.4W |
| Construction & Fit |
| Frame size |
NH1 |
| Poles |
2 |
| Type of installation |
Baseplate mounting |
| Cable terminal |
Flat terminal, M10 |
| Direction of cable terminal |
Variable (top or bottom) |
| Fuse monitoring |
None fitted (accessory-compatible) |
| Degree of protection (front fitted with clamp/lateral cover) |
IP20C |
| Dimensions (H x W x D) |
298 x 138 x 117mm |
| Mounting position |
Vertical or horizontal |
| Environmental & Standards |
| Product standard |
IEC / DIN EN 60947-3 |
| Ambient temperature range |
-25°C to +70°C (derating applies above rated ambient) |
| Altitude |
Up to 2,000m |
| Pollution degree |
3 |
| Overvoltage category |
III |
| Electrical endurance |
200 switching cycles |
| Mechanical endurance |
1,600 total switching cycles |
| Housing material |
Temperature-resistant to 125°C, self-extinguishing to UL94, CTI 600 tracking resistance, halogen-free |
| Ordering Information |
| Type designation |
KETO-1-2/F |
| Manufacturer article number |
T100112002 |
| Applicable for fuse-links |
NH1 (160A–250A gG) |
| MPN / SKU |
KETO-1-2/F |
Does this product include fuse-links?
No. The KETO-1-2/F is the switch-disconnector body only. It requires two NH1 fuse-links (sold separately) selected to suit the battery or inverter circuit's maximum design current.
What is the correct DC voltage rating for this switch?
Jean Müller's manufacturer datasheet for the KETO-1-2/F specifies a rated operating voltage Ue of 250V DC under utilisation category DC-22B. Please see the amber note above regarding differing figures quoted by some resellers, and confirm against the rating plate for your specific unit before final system design.
Can this switch be DIN rail mounted?
The KETO-1-2/F is designed primarily for baseplate mounting. Jean Müller also offers DIN-rail-mount variants within the wider KETO-1 range (e.g. busbar-mount and rail-mount versions) — if DIN rail fitting is required, please confirm the exact variant needed before ordering.
What size cable can this switch terminate?
The M10 flat terminals on the KETO-1-2/F accept the cable lug sizes commonly used with 25–150mm² DC cable, consistent with the wider KETO size 1 platform; always size cable and lugs to the fuse rating and local wiring regulations.
Is this switch suitable for outdoor or damp installation?
The base unit is rated IP20C with its covers fitted, which is an indoor/enclosure rating only. For outdoor or exposed installation, the unit must be fitted inside a suitably rated enclosure.
