Jean Muller Fuse-switch-disconnector KETO size 1 body (battery isolator)
Jean Muller Fuse-switch-disconnector KETO size 1 body (battery isolator)
Jean Muller Fuse-switch-disconnector KETO size 1 body (battery isolator)
Jean Muller KETO fuse-switch-disconnector — Isolation and fuse protection in one body — the fuses are a separate order.
Between a battery and the inverter it feeds there has to be something that will both break the circuit on demand and clear a fault. On a 48 V lithium bank running hundreds of amps of DC, that is not a job for an AC device: DC does not cross zero, so the arc has to be driven out rather than waited out.
Please read before ordering
About the Jean Muller KETO fuse-switch-disconnector
The KETO is a fuse-switch-disconnector, which is two things in one body. Pull the handle and the circuit is isolated for maintenance, visibly and lockably. Leave it closed and the NH fuse-links inside it are the overcurrent protection between the battery and the inverter.
Jean Müller build them to DIN EN 60947-3 and type-test them with gG NH links, which is what allows a published short-circuit rating rather than an assumed one.
Both bodies here are sold empty. Two fuse-links of the right size go in, and they are sized from the maximum battery current with a safety factor — not from what the switch could carry. If you would rather not size and order them separately, the pre-fused assemblies carry a body and two matched links on one part number.
What does this fit?
This is the isolator and fuse carrier that sits between a battery and its inverter.
A KETO body is sold without fuses. It takes two NH fuse-links of the matching size — NH00 links in a KETO-00, NH1 links in a KETO-1 — and they are chosen from the maximum battery current with a safety factor applied, not from the switch's own rating.
The products it is ordered with:
What the job needs
The details that decide whether this suits the system:
- The body ships with no fuses. Two NH links of the matching size are required: NH00 for the KETO-00, NH1 for the KETO-1.
- Size the links from the maximum battery current with a safety factor applied. The switch rating is a ceiling, not a selection.
- KETO-1 is rated AC690 / DC440, 250 A operational. Utilisation categories are DC-21B at 440 V / 250 A and DC-22B at 250 V / 250 A, so the usable DC voltage depends on the switching duty.
- KETO-1 flat terminal is M10 at 30 – 35 Nm. Clamp options run from 25 mm² to 150 mm² Al/Cu depending on the terminal fitted.
- KETO-1 is IP20 in service, IP2XC with the clamp and lateral covers, and IP10 with the switching element open. Keep 20 mm laterally and 50 mm above to earthed conductive parts.
- KETO-1 short-time withstand is 8.6 kA for 1 s, and rated conditional short-circuit current is 120 kA at 500 V.
- Ambient is −25 °C to +55 °C, with reduced operating current above 35 °C. Pollution degree 3, overvoltage category III, up to 2,000 m.
- KETO switches are moving from blue to black. During the transition either colour may be delivered; they are otherwise the same part.
Where this earns its place
The KETO fuse-switch-disconnector is specified most often for these jobs.
Things worth knowing about this listing
- The KETO-1 is supplied without fuses. It takes two NH1 links up to 250 A, sized from the maximum battery current with a safety factor applied.
Jean Muller KETO-1 body technical data
Questions we get asked about this inverter
Does it come with fuses?
No. A KETO body is sold empty. It needs two NH links of the matching size — NH00 for the KETO-00, NH1 for the KETO-1. The pre-fused assemblies are listed separately if you would rather buy them together.
Which size do I need?
KETO-00 takes NH00 links and handles up to 160 A. KETO-1 takes NH1 links and is rated 250 A. Choose by the fuse rating the battery needs, then take the body that carries it.
Is the DC rating 250 V or 440 V?
Both, depending on duty. The KETO-1 is rated DC440 operationally, with utilisation category DC-21B at 440 V / 250 A and DC-22B at 250 V / 250 A. DC-22B is the harder duty, which is why the lower voltage is quoted against it.
How do I size the fuse?
From the maximum battery current with a safety factor applied, and within the link ratings the body accepts. It is the battery and cable that set it, not the switch.
Why is mine black and the last one blue?
Jean Müller are moving the KETO range to black. During the transition either colour may be delivered; the part is otherwise unchanged.
Documents, advice and trade pricing
Every datasheet, certificate, installation manual and warranty document we hold for this product is in the Documents tab below. See the rest of our storage range, our hybrid inverters and our batteries, or email sales@clearraysolar.com if you would like us to check a pairing before you order.
Build your complete solar system
Everything you need in one place.
- Inverters
- Batteries
- Mounting Systems
- Cabling & Accessories
- Protection Devices
Delivery times vary by region:
- UK — 1-2 business days
- Highlands & Islands — 1-2 business days
Returns accepted within 14 days of delivery for unused items in original packaging.
