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"Do you have the same amps?" is one of the questions we hear most. The answer is usually yes, but the same amperage alone does not make an equivalent. A wrong equivalent shows up not when it is fitted but at the first fault. Below are the headings we check before any swap.
| What to check | Why it matters | Where it is stated |
|---|---|---|
| Rated current and voltage | Basic compatibility | Device front face |
| Breaking capacity (Icu/Ics) | Withstand under short circuit | Front face, kA value in a box |
| Trip curve (B/C/D) | Response to inrush | The letter before the rating |
| Pole count and neutral | 3P or 3P+N, whether N is switched | Part number and body |
| Mounting dimensions and depth | Fitting the existing panel | Datasheet, dimensional drawing |
| Auxiliary contact options | Keeping the signalling circuit unchanged | Accessory catalogue |
| Certification and specification | For acceptance and inspection | Product documentation |
Most often missed: breaking capacity
Devices exist at the same amperage with different breaking capacities; the 6 kA, 10 kA and 25 kA versions look almost identical. Breaking capacity must exceed the prospective fault current at that point. Near the transformer that value is high and falls with distance as cable impedance grows. Fitting a low-kA device where a high fault current is expected means the device disintegrates during a short circuit.
Coil voltage on contactors, output type on sensors
- Contactor — even with matching current, a different coil voltage (24 V DC, 230 V AC) means it cannot go into the circuit.
- Sensor — receive NPN instead of PNP and the PLC input never sees the signal; the device is sound but does nothing.
- Relay — a different contact arrangement (1CO, 2CO) or socket type will not seat in the existing base.
- Drive — single or three phase input; the same kW may be built for two different supplies.
When the specification names a brand
On public works and large investment projects the specification often names the brand. In that case we do not propose equivalents; if the product is rejected at acceptance, the cost far exceeds the material difference. Where no brand is mandated, we present equivalents comparatively with their technical differences and lead times, and the decision stays with you.
When a domestic equivalent is the right choice
Domestically produced items can be favourable on lead time, spare availability and price. At non-critical points — standard distribution boards, lighting and socket circuits — they are usually the right choice. Where high breaking capacity is required, where discrimination has been calculated, and in panels built by machine makers who export, an imported brand is preferred, because there the documentation and compliance are part of what is sold.
Send the part number or a photo of the item you want to replace; we will set out the alternatives that do the same job with their technical differences side by side. Distributing and selling eighteen brands, we can offer several budget levels for the same requirement.
Frequently asked questions
Does an equivalent affect the warranty?
A product's warranty comes from its own manufacturer, and being an equivalent does not affect it. What does matter is putting an equivalent inside a system: if a fuse other than the type specified is fitted on a drive's input, warranty on a drive failure becomes arguable. That is why, on protective devices that are part of a system, we follow the manufacturer's list.
Can a newer series replace an older one from the same brand?
Usually yes; manufacturers publish cross-reference tables at series transitions. Two things to watch: mounting dimensions may have changed, and accessories (auxiliary contacts, shunt trips) may not fit the old series. Where it must drop into an existing panel, we compare the dimensional drawings.
Is it worth asking about an equivalent for a single item?
Of course. We run the same checks for a single failed device; when a line is down, an alternative in stock can be worth more than an original with a long lead time. Send the part number and we will state stock along with the alternative.
How should I weigh the price difference when an equivalent is proposed?
Look at where the difference comes from. If it comes from breaking capacity, certification scope or expected life, the cheaper option genuinely offers less. If it comes from brand premium or import cost, the difference is not technical. We state that distinction in writing, line by line, in the quotation so the decision is informed.