Phoenix Contact MSTB 5.08 vs PT 2.5 PCB Terminal Blocks

By the IC Source Direct supply-chain desk · Data through September 2026

When a control-cabinet builder in Suzhou replaces a legacy Phoenix Contact MSTB 2.5 / 5.08 header strip with the newer PT 2.5 push-in family, they are not just changing a part number; they are re-engineering the field-replacement story. MSTB is a pluggable screw-flange header with a separable socket housing; PT 2.5 is a push-in, single-piece spring cage that the wire slides into with a screwdriver release. Both still anchor thousands of new PLC, drive, and IO-board designs every quarter, but the supply picture — and the buyer decision tree — has tightened through 2026 as Phoenix Contact's Blomberg lines keep absorbing COMBICON backorders.

This guide walks through the MSTB 5 mm and 5.08 mm families you can still book off our shelf, the PT 2.5 push-in counterpart that Phoenix Contact introduced to compete with Weidmüller SNAP IN and WAGO 2002 series, and the cross-reference playbook a procurement engineer actually needs in 2026.

MSTB 5 mm and 5.08 mm pluggable family at a glance

The MSTB header family is the workhorse of three Phoenix Contact sub-ranges. All four share the COMBICON plug-in footprint so a panel-builder can pick a header (MSTBA right-angle, MSTBVA vertical, or MSTB straight-through) and pair it with an MSTBT or MVSTBR plug socket of the same pitch.

MSTBA 2.5 / 5.08: right-angle male headers, 12 A / 320 V IEC nominal, UL 94 V-0 PA housing, through-hole solder tails. 2.5 mm pitch for signal, 5.08 mm pitch for power.
MSTBVA 2.5 / 5.08: vertical male headers, same electrical envelope, footprint mirrored for top-entry plugs.
MSTBT 2.5 / 5.08: female plug with screw clamp, 12 A / 630 V IEC, 5.08 mm pitch on the through-board power side. Field-wireable; mates with MSTB, MSTBA, MSTBVA headers.
MSTBC 2.5: female plug with crimp termination; uses the 3190551 / MSTBC-MT tin-plated socket contacts. Lower wire-resistance than screw clamp; preferred when the harness is built offline on a crimp applicator.

The catalog also surfaces a small MSTBVA vertical header family (Phoenix Contact part number 1924363, 8 positions, 5.08 mm pitch, 16 A / 400 V IEC, polyamide housing, UL94 V-0) that we can dispatch from our Shenzhen bonded warehouse. The matching MSTBT plug on the same 5.08 mm grid is Phoenix Contact 1786938 (12 positions, 5 mm pitch for signal, rated 12 A / 630 V IEC) or 1786857 (4-position variant) and 1786831 (2-position) — both stocked on the same shelf.

The point most buyers miss: MSTB 5 mm and MSTB 5.08 mm are not mechanically interchangeable. The shroud keyway and the contact spacing differ by 0.08 mm. Mixing them forces a wider PCB cut-out, and Phoenix Contact's own datasheet warns the 12 A current rating on the 5.08 mm plug only applies with the 5.08 mm header — plugging a 5 mm MSTBT onto a 5.08 mm MSTBVA will pin-block the contact and lift the contact normal force.

Catalog evidence — Phoenix Contact MSTBVA, MSTB, MSTBT, MSTBC in stock

Pulled directly from our cms-agent / Payload product index on September 7, 2026. Prices are IC Source Direct's bonded warehouse tier, in USD:

Part number	Series	Description	Pitch	Positions	Current IEC	Voltage IEC	Price (1 / 100 / 1,000)
1924363	COMBICON MSTBVA	Term block header 8-pos vertical, shrouded	5.08 mm	8	16 A	400 V	$3.76 / $2.64 / —
1924347	COMBICON MSTBVA	Term block header 6-pos vertical, shrouded	5.08 mm	6	16 A	400 V	$3.56 / $2.50 / —
1924321	COMBICON MSTBVA	Term block header 4-pos vertical, shrouded	5.08 mm	4	16 A	400 V	$3.04 / $2.13 / —
1786938	COMBICON MSTB	Term block plug 12-pos straight, screw clamp	5.00 mm	12	12 A	630 V	$5.21 / $3.66 / —
1786873	COMBICON MSTB	Term block plug 6-pos straight, screw clamp	5.00 mm	6	12 A	630 V	$3.00 / $2.10 / —
1786857	COMBICON MSTB	Term block plug 4-pos straight, screw clamp	5.00 mm	4	12 A	630 V	$2.07 / $1.45 / —
1786844	COMBICON MSTB	Term block plug 3-pos straight, screw clamp	5.00 mm	3	12 A	630 V	$1.72 / $1.21 / —
1786831	COMBICON MSTB	Term block plug 2-pos straight, screw clamp	5.00 mm	2	12 A	630 V	$1.36 / $0.95 / —
3190551	COMBICON MSTBC	Contact socket crimp, tin-plated, AWG 20-26	n/a	n/a	n/a	n/a	$0.18 / $0.13 / $0.10

All eight in stock at our Shenzhen bonded warehouse as of September 7, 2026, with MOQ 1 piece on the headers and MOQ 1 piece / 4,000-piece reel on the MSTBC crimp contacts. Sample requests on the MSTBVA vertical headers typically ship in 3 to 5 working days for engineering qualification.

MSTB vs PT 2.5 — when pluggable still beats push-in

PT 2.5 (and its 5.08 mm sibling PT 5.08) is Phoenix Contact's push-in spring-cage series, directly competitive with Weidmüller SNAP IN and WAGO 2002. It cuts wiring time on the cabinet side — a stripped solid or ferruled wire pushes into the spring cage with audible click — and is the right call when:

The cabinet is built in volume with pre-fabricated ferruled leads.
Field service is rare (the wires are not designed to be unplugged and replugged thousands of times).
Cabinet space is at a premium and you want to skip the mating plug.

MSTB pluggable still wins when:

The PCB module needs field serviceability. A field tech can pull the MSTBT plug out of the MSTBVA header and swap the IO card without desoldering.
The harness is built in one factory and the cabinet is built in another. The pluggable interface decouples the two assembly lines.
The signal includes a mix of power and low-level analog on the same board, and you want different pin counts on the same connector footprint.

The trap: PT 2.5 push-in and MSTB 5.08 pluggable have the same 5.08 mm grid, but the through-board pin pattern differs, so a PT 2.5 PCB footprint will not accept an MSTBVA header. The datasheet cross-reference is on page 14 of the COMBICON selection guide.

2026 supply picture for MSTB 5.08 mm headers

The MSTB and MSTBVA 5.08 mm headers on Phoenix Contact's Blomberg line were running 14-week lead times in late 2024 and have shortened to 4 to 6 weeks through Q3 2026 as Phoenix Contact added a second wave-solder line in spring 2025. The MSTBT plugs (5.08 mm and 5 mm) are running 3 to 4 weeks off the same line and we are holding them in stock at the bonded warehouse for Shenzhen dispatch. MSTBC crimp contacts remain the tightest of the three — Phoenix Contact's automatic crimp-applicator tool is still on allocation in EMEA, but the loose-piece 3190551 contacts (4,000-piece reel) are readily available from Shenzhen.

Price action: Phoenix Contact raised MSTB 5.08 mm list by 4.6% in March 2026, in line with the EUR-denominated cost push from the mid-2025 brass and PA66 resin spike. Our bonded warehouse price for 1924363 / 8-position MSTBVA has held flat through Q3 2026 at $3.76 per piece at unit, $2.64 at 100 pieces, $2.41 at 250 pieces. The MSTBT 5 mm plug family (1786831 / 1786844 / 1786857) has held flat at $1.36 to $2.07 across the same horizon.

Cross-references for MSTB 5.08 mm plug-in headers

Three alternatives a buyer should benchmark when MSTB 5.08 mm 16 A vertical headers hit an allocation:

Phoenix Contact MCVR 1.5 / MCVW 1.5: the 3.5 mm-pitch mini-pluggable family for low-current signal only (8 A / 160 V), not a drop-in for 5.08 mm power.
WAGO 231 / 721 series MCS: pitch-matched 5.08 mm male headers and female plugs, same 12 A / 630 V envelope, slightly different shroud keying.
Weidmüller Omnimate BL/SL 5.08: BL 5.08 socket block plus SL 5.08 header, screw clamp on the socket side, 12 A / 400 V IEC — slightly lower voltage rating than MSTB but pin-for-pin interchangeable on a redesigned PCB.

When the choice is between MSTB and WAGO 721, the deciding factor is usually the cabinet's existing plug-and-socket tooling. If the harness line is already running on Phoenix Contact crimp applicators (CTX CM 1.6 or CCX 2.5), stay on MSTB / MSTBC. If the line is on WAGO 897 or Weidmüller PZ 6, switch to the matching family and avoid mixed-terminus inventory.

Practical sourcing checklist for Q3 2026

For an industrial panel builder sourcing MSTB 5.08 mm pluggable in Q3 2026:

Confirm pitch first — 5.00 mm MSTB vs 5.08 mm MSTB are 0.08 mm apart in pin spacing and not interchangeable.
For signal-only boards, MSTB 5 mm headers can run up to 12 A / 630 V IEC and are stocked at our Shenzhen bonded warehouse.
For 16 A power boards, step up to MSTBVA vertical or MSTBA right-angle 5.08 mm headers; both rated 16 A / 400 V IEC.
Pre-order the matching MSTBT plug when you order the header. Phoenix Contact's Blomberg lines bundle the two on the same production run and a stock-out on the plug will idle the assembly line.
If you are switching from MSTB to PT 2.5 push-in, factor in a new PCB layout — the through-hole pattern is not compatible even at the same 5.08 mm grid.
For serviceable IO modules with frequent field swap, MSTBC crimp + MSTBT screw-clamp combination reduces contact resistance versus screw-clamp-only.

Data Notes

Catalog data: IC Source Direct cms-agent / Payload product index, snapshot 2026-09-07, part numbers 1924363, 1924347, 1924321, 1786938, 1786873, 1786857, 1786844, 1786831, 3190551.
Specifications (pitch, current, voltage, housing, UL94 rating): Phoenix Contact COMBICON MSTB and MSTBVA datasheets (Dwg 04-2024), cross-checked against Phoenix Contact's online product finder.
Lead-time and price action: Phoenix Contact Blomberg line lead-time bulletins (Q1 2025, Q1 2026) plus IC Source Direct bonded warehouse tier (USD, USD/CNY 7.18).
Sub-series taxonomy: COMBICON Selection Guide 2025, pages 12-18 (MSTB), 22-25 (MSTBVA), 26-29 (MSTBC).

Disclaimer: IC Source Direct is an independent distributor of Phoenix Contact products and is not an authorized distributor of Phoenix Contact. All part numbers, trademarks and registered trademarks are the property of their respective owners. Specifications and lead times are directional planning data — verify with your supplier before issuing a PO.

Languages: English