A 24 V panel rarely has just one load. Relays, sensors, control electronics and valve coils can draw different currents in different machine states. Before approving a 24V 10A DIN-rail power supply, build a state-based load record rather than adding a few convenient nominal numbers.
Start with the accepted supply and the actual branch
দ WEHO NDR-240 product table identifies the NDR-240-24 variant with a nominal 24 V, 10 A output. The retained authentic sample also reads NDR-240-24, with INPUT:100-240VAC 2.8A 50/60Hz and OUTPUT:24V followed by the original direct-current graphic and 10A. These are specimen markings, not proof that every cabinet, ambient condition or input situation can support a continuous 10 A branch.
Keep the order-applicable specification and installation requirements with the audit. Confirm the actual incoming supply, accepted output setting, enclosure environment and branch arrangement before deciding how much output current is usable. Do not transfer another NDR variant’s rating or assume that a family prefix is a load approval.
Illustrative heat-exchanger control bay: the NDR-240-24 is rear-DIN-mounted in a separate protected electrical compartment serving a conditional 24 V control branch. The adjoining instruments and valve equipment establish the engineering context; no pictured device current or tested skid-load result is claimed.
Create one record for each connected device
Use the actual device model and its manufacturer’s current data. Separate a relay coil from whatever its contacts switch. Record a sensor’s supply demand separately from the load on an output channel. For a solenoid valve, identify the coil variant, energization state and any separately documented pull-in or reduced-hold behavior; do not assume that all coils have the same demand. A valve or sensor icon on a drawing is not a current value.
Include control-board consumption, interface modules and other loads that remain powered while the machine is idle. If a current value is unavailable, mark that row as unresolved and obtain the relevant device evidence or a qualified measurement. An unresolved row must not silently become zero.
| Audit field | What belongs in the record |
|---|---|
| Identity and branch | Exact load model, supply voltage, terminal or branch reference and return path |
| Operating-state demand | Documented idle, active and switching demand, including the conditions and units |
| Simultaneous operation | Which loads are energized together in each real machine state |
| Evidence and uncertainty | Manufacturer document revision, measurement conditions and unresolved values |
| Acceptance basis | Order-linked supply limits and the equipment builder’s approved design requirements |
Sum real machine states, not the longest parts list
For each state, add the currents of the loads that actually coincide: the continuously powered group plus the group energized in that state. Evaluate startup, normal operation, actuator transitions, stop and any other state relevant to the equipment sequence. A short transient and a continuous draw are different observations; one must not be used as evidence for the other.
This is not an invitation to apply an arbitrary diversity factor. An interlock or timing sequence only removes simultaneous demand when it is genuinely part of the accepted control design. Conversely, simply adding every installed coil as though all operate continuously may obscure which state really drives the design. Keep the sequence assumptions visible so that a later PLC-program or device change triggers a new audit.
A different pneumatic assembly-cell control bay illustrates another conditional 24 V auxiliary branch. The supply position, supported source view, adjacent devices and machine context differ from the heat-exchanger scene. It is a source-referenced illustration, not evidence that an unnamed valve manifold has passed a load test.
Check the supply output and the remote load separately
A satisfactory sum does not prove that every load sees an acceptable voltage during a switching event. The branch circuit also has conductors, terminals, protective devices and return paths. Record voltage and current at the points relevant to the actual question, using a qualified measurement setup. A reading at the supply terminals is not automatically the same reading at a remote coil or controller.
Compare the completed evidence with the accepted supply and load requirements. This article deliberately supplies no invented current budget, spare-current percentage, cable size, protective-device setting or universal switching-response limit. Those decisions require the actual equipment design and applicable installation rules; they cannot be derived from the product’s 10 A nameplate alone.
Keep revision differences visible before cabinet fit approval
The retained complete supplier mechanical drawing for this sample shows a 63 mm front width, 125.2 mm upright height and 113.5 mm front-to-rear depth, with a real rear DIN hook and spring latch. That drawing controls the source-referenced illustration. The current public page separately lists a conflicting 125.2 × 125.2 × 100 mm tuple. The disagreement is not resolved here, and the illustration must not be presented as proof of a universal drop-in fit. Confirm the order-applicable drawing with the supplier before accepting cabinet space, clearance or replacement compatibility.
The physical sample also prints a 24–28 V adjustment legend, whereas the public table describes a different adjustment range. Preserving that genuine printed legend does not authorize a guaranteed delivered adjustment range. Generic input, environmental and withstand-voltage statements differ across the retained documents too; they are not combined into a more favorable performance specification. The article’s verified product reference remains the exact nominal NDR-240-24 specimen and a load-audit method, not a certification or installation approval.
What to send with a supplier or internal review
Send the exact NDR-240-24 identifier, accepted document revisions, incoming supply conditions and the state-based load sheet. Include the device-model evidence, unresolved rows, observed switching behavior and remote-load observations that matter to the equipment requirement. State any cabinet-fit or revision disagreement explicitly. This gives a reviewer something testable; “24 V, about ten amps” does not.
Frequently asked questions
Does a 10 A nameplate mean every panel can use 10 A continuously?
No. Confirm the accepted full-model conditions and actual installation. The nameplate alone does not close an input, thermal, branch or load-compatibility review.
Should I add every relay and valve current together?
Build documented machine states and add the loads that coincide in each state. Do not invent diversity, omit unknown rows or treat a transient as a continuous value.
Does the relay contact rating belong in the coil-current total?
No. Identify the actual supply demand of the coil or control device separately from what its contacts switch.
Why measure at a remote load as well as at the supply?
They are different points in the branch circuit. The question may concern the load’s observed voltage during a real transition, not just the supply-terminal reading.
Which dimensions should I use when the public page and drawing disagree?
Do not choose silently. Preserve both references and obtain the controlled drawing applicable to the actual order before approving fit.
Are these verified customer-installation photographs?
No. They are source-referenced application illustrations. Product identity, visible mounting and wiring are reviewed against genuine sources, but the scenes do not establish a customer test, energized-installation approval or human publication approval.
