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The only switch here citing a standard

HELLA S33 key-operated isolator, 1000 A for 10 s at 12 V, DIN/ISO 40050-IPX2

A key-operated battery isolator for positive or negative lines, rated 1000 A for ten seconds at 12 V, built to DIN/ISO 40050-IPX2 with two screw terminals.

HELLA S33 battery isolator with a red key

HELLA S33 key-operated isolator, 1000 A for 10 s at 12 V, DIN/ISO 40050-IPX2

A key-operated battery isolator for positive or negative lines, rated 1000 A for ten seconds at 12 V, built to DIN/ISO 40050-IPX2 with two screw terminals.

Continuous
Not published as a single figure — instead the listing gives the supply cross-section for each continuous current: 35 mm² at 100 A, 70 mm² at 250 A, 250 mm² at 500 A, fourth bullet
Intermittent current
Maximum 1000 A for 10 seconds at 12 V, sixth bullet
DC voltage rating
12 V, sixth bullet
Load-switching capability
Nowhere in the listing; it switches battery and ignition current, first bullet
Terminals
Two screw studs, two nuts supplied per stud, third bullet
Mounting
Panel-mounted, rotary operation, from the title
Operation
A red key, removable in the off position; either the positive or the negative line can be switched, first and second bullets. DIN/ISO 40050-IPX2, seventh bullet
Amazon reference
B004K1ND2C (same reference on 6 Amazon marketplaces)
EAN
4082300002508
  • The only switch in this catalogue to cite a standard: DIN/ISO 40050-IPX2
  • Supply cross-sections published against three current levels — it tells you what to wire it with
  • No single continuous rating, so the figure has to be read off the cross-section table

Best for: A workshop or commercial vehicle where the isolator has to be locked off.

≈ $22 / €15
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Specifications

Continuous
Not published as a single figure — instead the listing gives the supply cross-section for each continuous current: 35 mm² at 100 A, 70 mm² at 250 A, 250 mm² at 500 A, fourth bullet
Intermittent current
Maximum 1000 A for 10 seconds at 12 V, sixth bullet
DC voltage rating
12 V, sixth bullet
Load-switching capability
Nowhere in the listing; it switches battery and ignition current, first bullet
Terminals
Two screw studs, two nuts supplied per stud, third bullet
Mounting
Panel-mounted, rotary operation, from the title
Operation
A red key, removable in the off position; either the positive or the negative line can be switched, first and second bullets. DIN/ISO 40050-IPX2, seventh bullet
Amazon reference
B004K1ND2C (same reference on 6 Amazon marketplaces)
EAN
4082300002508

A key switch with the wiring published alongside the rating.

The table nobody else prints

35 mm² at 100 A. 70 mm² at 250 A. 250 mm² at 500 A.

Three pairs of numbers in the fourth bullet. They say what the switch carries and what to bring it in on, together — and undersized tails are how a correctly rated switch ends up hot.

The standard

DIN/ISO 40050-IPX2. Across twenty-one accessories in this catalogue, one listing cites a standard, and this is it. IPX2 is modest protection — dripping water at an angle — and it is a stated rating rather than the word “waterproof”.

The key

Red, removable in the off position. That makes it a lock-off: the circuit cannot be brought back by someone leaning on the switch. A replacement key part number is published too, 9SL 706 729-031.

The surge

Maximum 1000 A for 10 seconds at 12 V. A figure with a duration and a voltage, which is the honest form.

Either side

Positive or negative line, selectable. Two screw studs, two nuts each. Lugs are not included.

Availability

German, French, Italian and Spanish Amazon stores quoted 15 € to 24 € when this page was compiled.

American and British Amazon stores carry it too, priced in their own currency, which the euro range above deliberately omits.

These figures are what Keepa reported on the day this page was last updated. Availability and pricing move without notice.

Prices quoted in this text were read on 16 September 2026. The live price is at the top of the page.

More battery isolator switches

  • ProPlus two-pole NATO-type battery isolator with a key

    ProPlus Two-pole NATO-type isolator, 500 A continuous / 2500 A peak, with key

    A two-pole NATO-type battery isolator rated 500 A continuous and 2500 A peak, supplied with a key, covering 6 V to 48 V systems.

    Continuous
    500 A, third bullet — the highest continuous rating in this family
    Intermittent current
    2500 A peak for short periods, second bullet
    DC voltage rating
    6 V, 12 V, 24 V, 36 V and 48 V, first bullet — the widest voltage coverage here, and the only switch to reach 48 V
    Load-switching capability
    Nowhere in the listing; it is described as an emergency-stop switch, from the title
    Terminals
    Nowhere in the listing
    Mounting
    Two-pole, NATO type, from the title
    Operation
    A key is included, first bullet
    Amazon reference
    B0198UJ3AU (same reference on 5 Amazon marketplaces)
    EAN
    8718546657245
    • 500 A continuous and 2500 A peak — both published, and the highest pair in this family
    • Rated to 48 V, the only switch here that covers a 48 V battery bank
    • The terminals are not described at all, on a 500 A switch

    Best for: A 48 V bank or a heavy vehicle installation where both poles should break at once.

    ≈ €20
    Check price on Amazon
  • QWORK wireless remote battery isolator with two key fobs

    QWORK Remote-controlled isolator, 240 A, two fobs, 20 mA standby

    A wireless remote-controlled 12 V battery isolator rated 240 A with 300 A instantaneous, drawing 20 mA on standby and cutting off automatically below 7.8 V.

    Continuous
    240 A nominal, first bullet
    Intermittent current
    Up to 300 A instantaneous, first bullet
    DC voltage rating
    12 V, first bullet
    Load-switching capability
    Absent as a rating; the remote disables above 12 V for safety, third bullet
    Terminals
    Nowhere in the listing
    Mounting
    Nowhere in the listing
    Operation
    Two wireless remotes, first and fifth bullets; standby consumption 20 mA, automatic cut-off below 7.8 V, operating temperature 30° to 90°. CR2016 cells not included
    Amazon reference
    B0DFPV614Y (same reference on 4 Amazon marketplaces)
    EAN
    0795973840387
    • The standby draw is published — 20 mA — which is the figure a remote isolator has to answer for
    • An automatic low-voltage cut-off at 7.8 V
    • A remote isolator draws current permanently, which is the opposite of what an isolator is for

    Best for: A vehicle whose battery sits somewhere awkward and is isolated often.

    ≈ €22
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  • Spurtar battery terminal isolator in green for a negative post

    Spurtar Terminal isolator, 125 A continuous / 500 A brief, 15–17 mm

    A battery terminal isolator in copper-zinc alloy rated 125 A continuous and 500 A for short periods, for negative posts of 15 to 17 mm.

    Continuous
    125 A, first bullet
    Intermittent current
    500 A for short periods, first bullet
    DC voltage rating
    12 V and 24 V, first bullet
    Load-switching capability
    Nowhere in the listing
    Terminals
    Clamps to a negative post of 15 to 17 mm, second bullet
    Mounting
    None — it sits on the battery terminal itself
    Operation
    Turn the green knob to disconnect quickly and safely, fourth bullet
    Amazon reference
    B075CK7W3Z (same reference on 5 Amazon marketplaces)
    EAN
    0655302160992
    • Both current figures published — 125 A continuous and 500 A brief
    • Copper-zinc alloy named
    • Negative post only, which suits most vehicles and not a positive-earth installation

    Best for: A vehicle or caravan battery isolated between uses, at a hundred amps or less.

    ≈ £7 / €9
    Check price on Amazon

Others on the same shelf

  • RTSHUK pure copper battery terminals in three pairs

    RTSHUK Three pairs of pure copper terminals, marked polarity, threaded

    Three pairs of pure copper battery terminals with marked polarity and a threaded post, intended for battery extension, parallel connection and earthing.

    Post type
    Standard posts, from the title; 12 V and 24 V named
    Size
    Nowhere in the listing
    Material
    Pure copper, third bullet, named for corrosion resistance, durability and conductivity
    Plating
    Nowhere in the listing
    Cable range
    Nowhere in the listing
    Clamping method
    A thread on the clamp eases assembly, second bullet
    Extra outputs
    Not as separate posts; the second bullet names battery extension, parallel connection and earthing as the intended uses
    Corrosion protection
    Copper named as corrosion resistant; the third bullet also claims it avoids voltage distortion
    Amazon reference
    B0FJXQJLXF (same reference on 5 Amazon marketplaces)
    EAN
    0607604977396
    • Three pairs, which is the quantity a parallel bank of two or three batteries needs
    • Polarity clearly marked on each clamp
    • No post diameters

    Best for: Building a parallel bank of two or three batteries in one purchase.

    ≈ €12
    Check price on Amazon
  • Larebidtex universal battery terminals with bolts

    Larebidtex Pair of universal terminals with bolts, for vehicle, boat and motorhome

    A pair of universal battery terminals with bolts, offered for cars, boats, motorhomes and caravans, with no specification published in the listing.

    Post type
    Nowhere in the listing
    Size
    Nowhere in the listing
    Material
    Nowhere in the listing
    Plating
    Nowhere in the listing
    Cable range
    Nowhere in the listing
    Clamping method
    Described as having bolts, from the title; the size is not stated
    Extra outputs
    Nowhere in the listing
    Corrosion protection
    Nowhere in the listing
    Amazon reference
    B0FGQ7DNZC (same reference on 5 Amazon marketplaces)
    EAN
    0721820978866
    • The intended vehicles are named — car, boat, motorhome, caravan
    • A pair rather than a single terminal, so both posts are covered
    • The listing has no bullet points at all — every specification line is empty

    Best for: Nothing this page can identify, which is the finding rather than a judgement on the product.

    ≈ €11
    Check price on Amazon
  • Aigreat busbar pair in red and black with clear covers

    Aigreat Pair, 250 A at 12 V, 48 V max, 4 × M8 plus 3 screw terminals

    A red and black busbar pair rated 250 A at 12 V with a 48 V DC maximum, each with four M8 studs and screw terminals, in nickel-plated brass with covers.

    Current rating
    250 A when working in a 12 V circuit, second bullet
    Studs
    Four M8 bolt terminals and three number 8 screw terminals per bar, fifth bullet
    Material
    Brass busbar plates, third bullet
    Plating
    Nickel-plated, for low contact resistance, third bullet
    Cover
    Supplied with a cover, from the title
    Mounting
    Nowhere in the listing
    Pole separation
    Supplied as a pair — one red positive bar and one black negative bar, first bullet — so the poles are physically separate units
    Amazon reference
    B0F6SMQ4P3 (same reference on 6 Amazon marketplaces)
    EAN
    0717504929859
    • A pair, red and black, so both poles are covered in one purchase
    • Eight ring terminals included, plus screw terminals on each bar
    • The mounting is not described

    Best for: A 12 V installation where four heavy feeds leave each pole.

    ≈ £24 / €26
    Check price on Amazon

All battery isolator switches