Allen-Bradley SLC 500 · Lifecycle briefing

1746-P4, P2 and P1: discontinued, and two have no replacement

All three SLC 500 rack power supplies are discontinued: the 1746-P4 and 1746-P2 on September 30, 2024, and the 1746-P1 on September 30, 2020.

1746-P4 and 1746-P2 both carry 'No planned RA replacement.' 1746-P1 is listed under 'Engineering Replacement' with no successor product named on the lifecycle page.

The practical position: it is worth knowing exactly which supplies you run and how many spares you actually hold.

Verified lifecycle facts

Rockwell Automation lists the 1746-P4 as Discontinued as of September 30, 2024, with the replacement category 'No planned RA replacement.' Rockwell's product description reads '1746 SLC System, Power Supply - Rack Mount, 120/240 VAC, 10A.' Separately, Publication 1747-UM011G-EN-P gives the 1746-P4 an internal current capacity of 10.0 A at 5V dc and 2.88 A at 24V dc, noting that the combination of all output power — 5 volt backplane, 24 volt backplane and 24 volt user source — cannot exceed 70 watts.

Rockwell lists the 1746-P2 as Discontinued as of September 30, 2024, replacement category 'No planned RA replacement.' Description: '1746 SLC System, Power Supply - Rack Mount, 120/240 VAC, 5A.' Publication 1747-UM011G-EN-P gives an internal current capacity of 5 A at 5V dc and 0.96 A at 24V dc.

Rockwell lists the 1746-P1 as Discontinued as of September 30, 2020, under 'Engineering Replacement,' with no successor product named on the lifecycle page. Description: 'SLC Rack Mounting Power Supply.' Publication 1747-UM011G-EN-P gives an internal current capacity of 2 A at 5V dc and 0.46 A at 24V dc.

Catalog	Status	Discontinued	Replacement category	5V dc	24V dc	24V user	Combined limit	Source
1746-P1	Discontinued	2020-09-30	Engineering Replacement — no successor named	2 A	0.46 A	200 mA	—	Lifecycle page; UM011G p.177
1746-P2	Discontinued	2024-09-30	No planned RA replacement	5 A	0.96 A	200 mA	—	Lifecycle page; UM011G p.177
1746-P4	Discontinued	2024-09-30	No planned RA replacement	10.0 A	2.88 A	1 A	≤ 70 W total	Lifecycle page; UM011G p.177–178

Last verified August 5, 2026.

On the ratings, precisely

Rockwell's lifecycle pages carry only short product descriptions. The internal current capacities are published in Publication 1747-UM011G-EN-P: 1746-P1 — 2 A at 5V dc, 0.46 A at 24V dc; 1746-P2 — 5 A and 0.96 A; 1746-P4 — 10.0 A and 2.88 A. Among these three, the 1746-P4 carries the highest published internal current capacity. Rockwell notes that for the P4 the combination of all output power cannot exceed 70 watts, so its two maximum figures are not simultaneously available. Higher published capacity does not establish that one supply is a suitable substitute for another.

Meridian's caution — our read, not a manufacturer statement

Rockwell publishes different internal current capacities for the 1746-P1, P2 and P4, and the P4 additionally carries a combined-output limitation. Do not assume the three are interchangeable. Rockwell's own procedure is to total your chassis current draw and select a supply whose internal capacity exceeds it for both the 5V dc and 24V dc loads — see Publication 1747-UM011G-EN-P. Confirm suitability with Rockwell or a qualified controls professional.

Context — the rest of the rack

All verified on Rockwell's own product pages: chassis 1746-A7 discontinued 2024-03-31 with the replacement category "No planned RA replacement" · processors 1747-L532 / L542 / L551 / L553 — 2024-03-31 · scanners 1747-SN / 1747-SDN — 2024-03-31 · discrete I/O 1746-IB16 — 2021-12-31 and 1746-OB16 — 2024-09-30 · analog I/O 1746-NI4 / 1746-NO4I — 2021-04-29.

Meridian analysis — our read, not a manufacturer statement

Meridian's assessment: every SLC 500 catalog number checked for these pages—including the verified chassis, power supplies, processors, scanners and I/O modules—carries a discontinuation date. This is not a statement about every SLC 500 catalog number.

Replacement reality

What the lifecycle pages list: "No planned RA replacement" for the 1746-P4 and 1746-P2; "Engineering Replacement" with no successor product named for the 1746-P1.
Within the family: do not treat P1, P2 and P4 as interchangeable by assumption — see Meridian's caution above and the selection procedure in Publication 1747-UM011G-EN-P.
Third-party or "equivalent" supplies: we are not going to tell you a non-Allen-Bradley supply is safe in your rack. That's an engineering decision about your load, your enclosure and your application.

What to verify before you buy

Exact catalog number and series letter, confirmed against the unit in your rack.
Input voltage — confirm the rack is on 120/240 V AC and not a 24 V DC variant.
Actual module load in the chassis, totalled for both the 5V dc and 24V dc loads per Publication 1747-UM011G-EN-P. If the rack has grown since it was built, the original supply may already be marginal.
Whether the seller load-tested the unit, and what the warranty covers.

When you should not buy

A working supply with one spare on the shelf covers a single failure. If you have that, you're in reasonable shape; note the dates and move on.
Check what else is on the market before you commit. If a route other than buying from us is cheaper and fast enough, take it — we'd rather tell you that than sell you a unit you didn't need.
Do not substitute one supply for another on capacity alone — run the selection procedure in Publication 1747-UM011G-EN-P against your actual chassis load first.
If the line is funded for migration soon, deep spares are wasted money.

Meridian analysis — our read, not a manufacturer statement

Meridian's view: lifecycle status alone does not determine whether a facility should purchase a spare immediately. That decision depends on installed quantity, existing spare coverage, failure criticality and current sourcing lead time.

Critical-spare implications

The real question is how many chassis you run and how many can be down at once. A plant with eight SLC racks and one spare supply is not covered — it's covered for one event. Sites where a rack failure stops production are the ones that should hold more than one, and should know whether the spares they hold are the right rating for the racks they'd go into — verified per the selection procedure in Publication 1747-UM011G-EN-P.

What Meridian may be able to source

New-surplus, tested-used or refurbished 1746-P4 / P2 / P1, quoted as one delivered price with condition, warranty and lead time stated. We do not hold stock and will not promise a unit before a supplier confirms it.

Depending on the equipment and requirement, Meridian may research sourcing, exchange, manufacturer-supported migration, or third-party service options. Availability and suitability must be verified for each request.

Warranty terms vary by item, condition and supplier. Meridian confirms the applicable terms before purchase.

Need a 1746-P4, 1746-P2 or 1746-P1? Send the catalog number, quantity and required date to brian@meridiansources.com or call 713-305-9321. One delivered price, condition and warranty spelled out.

Critical-Spare Review — limited Phase 1 pilot

Not sure what your real exposure is? Send up to 5 catalog numbers and Meridian returns a preliminary lifecycle and sourcing review: verified lifecycle status and replacement classification for each, including the parts that don't warrant a spare.

Maximum 5 catalog numbers per review.
This is a limited Phase 1 pilot — a maximum of 3 free reviews will be delivered during Phase 1.
The review is preliminary and is not an engineering certification; compatibility and suitability require separate verification.
Meridian may not be able to source every submitted item.

Start at Submit a Part Request — include the catalog numbers in the request notes, or we will ask for the list after you reach out.

Disclaimer

Lifecycle and replacement information is for preliminary planning. Compatibility may depend on firmware, hardware revision, wiring, programming, network architecture, safety requirements, and the specific application. A manufacturer-listed successor may require modification or migration and may not be a direct drop-in replacement. Suitability must be verified with the manufacturer or a qualified controls professional.

Sources

Rockwell Automation product details — 1746-P4 (rockwellautomation.com/en-us/products/details.1746-p4.html). Accessed August 5, 2026.
Rockwell Automation product details — 1746-P2 and 1746-P1. Accessed August 3–5, 2026.
Rockwell Automation Publication 1747-UM011G-EN-P (June 2008), pp. 177–178 — internal current capacities, combined-output limitation, and the power-supply selection procedure.
Rockwell Automation product details — 1746-A7, 1747-L5xx, 1747-SN/SDN, 1746-IB16/OB16/NI4/NO4I. Accessed August 3–5, 2026.