Sizing a waterproof XLG LED driver starts with the electrical load and ends with the complete installation. Procurement teams should not choose by wattage and an IP marking alone. The required output behaviour, simultaneous fixture demand, input conditions and protected connections must all describe the same proposed system.
Confirm constant-voltage operation first
The official WEHO XLG-100 page describes a constant-voltage family and identifies XLG-100-24 at 24 V, 4.2 A, with 100.8 W in its output table. The authentic specimen carries the same model and output marking. It is not evidence that an arbitrary bare LED string can be connected as a constant-current load.
The page also contains a row headed “constant current range.” Do not turn that ambiguous row into a promised operating curve or an extra control mode. Confirm the current revision and the lighting product’s required supply type with the supplier. A model name is useful only when its electrical behaviour matches the actual fixture.
Build a load schedule, not a single guess
List each compatible lighting branch, its documented demand, quantity and operating pattern. Distinguish an illuminated sign operating continuously from zones that are switched separately. Add all loads that can run simultaneously, including any genuinely associated electronics. Do not assume that lighting branches remain separate simply because they occupy different physical parts of a sign.
For a purely illustrative calculation, four compatible 24 V branches drawing 0.6 A each total 2.4 A. That example does not establish the consumption of a particular fixture, a tested XLG assembly or a required universal percentage margin. Use actual fixture data and an engineering allowance appropriate to the operating conditions and anticipated changes.
Keep the continuous budget separate from startup and control transitions. Ask for the information needed to assess those conditions rather than interpreting a protective response as normal usable capacity. If the available fixture data is incomplete, the sizing decision remains conditional; a larger model name does not supply the missing evidence.
Check the source and the load ends separately
The photographed XLG-100-24 label states INPUT 95–264 VAC 2.2 A 50/60 Hz and OUTPUT +24 V with the original DC line symbol, 4.2 A. The frequency range given elsewhere in the specification is not a replacement inscription for the nameplate. Preserve each source’s meaning rather than editing the physical label to match a table.
Have the electrical designer review the project’s actual input source, circuit and applicable operating conditions. Do not infer identical usable output at every input and temperature from a headline input range. On the output side, assess connection losses and the voltage delivered to each fixture, particularly when branches extend to different areas of a sign or building-lighting assembly.
Describe the distribution and service isolation clearly. The driver does not decide how an installer protects every branch or identifies a failed fixture. Cable selection, protection and mains work require the matched documentation and qualified personnel; this article does not prescribe conductor sizes or protective-device values.
“Waterproof” is not the whole assembly specification
The real specimen carries IP67. That marking does not establish the protection of an external joint, enclosure entry or installed lighting system. Identify the actual exposure and the connection method before approving a project drawing. An indoor dry service compartment and an exposed outdoor joint are different design situations, even when they use the same marked driver.
Keep factory cable exits mechanically supported and do not add a dimming cable or terminal block that the source specimen does not have. The inspected unit uses fixed cable tails at opposite ends and flange fixing, not DIN-rail mounting. Its ribbed casing is not permission to place it against insulation or declare every mounting orientation thermally acceptable.
Resolve the mechanical revision before tooling
The complete drawing explicitly distinguishes a 166 mm body from a 190 mm overall span to the outer mounting-ear ends, with 49 mm width. The dimension row gives 34 mm height. Each cable tail is separately marked 180 ± 20 mm, followed by a 30 mm stripped section; those tails are not included in the 190 mm mounting envelope.
The general-table heading nevertheless says 170 × 49 × 34 mm. No 170 mm body dimension is identified in the drawing, so this is still an unresolved revision discrepancy—not “170 mm plus cables equals 190 mm.” The public page states 190 mm, but it does not close the delivered-unit revision. The scene concepts follow the documented flange/body relationship, not an approved installation or hole-drilling template.
Request a corrected, model-matched drawing before releasing mounting holes or a tight compartment. Confirm the real flange positions, cable space and access. Separating this mechanical question from the electrical load budget prevents a correctly sized output from being mistaken for an installation-ready order.
Record an auditable purchasing decision
The RFQ should include the exact model, compatible fixture information, simultaneous-load schedule, actual input, environment, connection requirements and matched mechanical revision. Keep measured commissioning results separate from nominal ratings. Purchasing can then compare proposals on the same basis without inventing certification, waterproofing or fixture-compatibility conclusions.
Frequently asked questions
Does a 100 W family name mean exactly 100 W for every output model?
No. Use the selected model’s documented voltage and current rather than treating the family headline as the full rating.
Is the IP67 marking enough to approve an outdoor installation?
No. The complete equipment, joints and installation conditions need their own assessment.
