Cords, Plugs and Switches: The Small Parts That Fail an Audit

Lamp programmes rarely fail on the things designers care about. They fail on cord type, plug polarity, strain relief and switch rating, because those items are usually copied from an older product without anyone checking them against the market the lamp is sold into.

Cord type is specified, not chosen

North American portable lamps use flexible cord rated for the application, typically an SPT-2 or SVT type for indoor use. The cord carries a temperature rating and a jacket thickness, and substituting a thinner jacket to save fractions of a cent is the kind of change that turns up in testing.

Polarity and grounding

A two-wire cord in North America should be polarized: one blade wider than the other. A three-wire cord adds an equipment ground and is required on some metal-bodied products. Reversing the wires inside the lamp is a real defect and a common one on samples assembled at speed.

Switches are the highest-wear part

A rotary switch on a floor lamp is the component a customer touches every day, and it is usually the first thing to fail. Switch rating should account for inrush current, particularly on LED drivers, which draw a brief surge far above their steady-state current.

Foot switches and reach

A foot switch on the cord is convenient and easy to specify badly. Pedal travel, force required and whether the switch survives being stepped on in shoes are all worth asking about, because this is where hospitality programmes generate maintenance tickets.

The short checklist before releasing a sample

Confirm cord length and type in writing, confirm polarisation, confirm the switch rating against the maximum wattage, and confirm the strain relief construction with a photograph from inside the base. None of this costs money at the sample stage and all of it costs money after the container ships.