JB8SPT TuffSeal® Signal Trim Junction Box

As of: Saturday, August 15, 2026

Standard Features

Transient protection
PreVent™ breather vent
Conformal-coated circuit board
Removable load cell connectors
Section and individual cell trim capability
Field-replaceable transient protection
One coupling, 0.5 in NPT cord grip to 0.75 in NPT conduit fitting for homerun cable
Connect two, four, six or eight single load cells (even number of load cells only)
Expansion port

Applications

Truck, livestock and railroad scales

WARNING: Cancer and Reproductive Harm California Proposition 65

Offering the ultimate protection for important load cell output, the JB8SPT TuffSeal® signal trim junction box with transient protection is the optimal choice for truck, livestock and railroad scales susceptible to potentially destructive outdoor elements. The TuffSeal Fiberglass Reinforced Polyester (FRP) NEMA Type 4X enclosure effectively protects sensitive circuit boards and allows easy access for signal trimming individually or by section. The included transient board protects circuitry from devastating power surges.

JB8SPT TuffSeal Signal Trim Junction Box Specifications

Cable Fittings:
(9) 3/8 in NPT 0.157 to 0.314 in
(2) 1/2 in NPT 0.272 to 0.472 in

Rating/Material:
NEMA Type 4X
Polycarbonate with overlapping solid cover, stainless steel screws

Connectors:
Pluggable screw type, 12 to 28 AWG

Trimming:
Individual cell trim

Temperature:
Operating:
0 to 122 °F (-18 to 50 °C)

Potentiometers:
100,000 ohms, 25-turn cermet

Circuit Board:
5.7 × 7.2 in with conformal coating

Warranty:
One-year limited

JB8SPT TuffSeal Signal Trim Junction Box Dimensions

Enclosure
A	12.13 in	E	9.32 in
B	11.45 in	F	5.98 in
C	11.38 in	G	6.95 in
D	10.59 in

Replacement Junction Boxes, Boards or Components Table

Model	Complete J-Box Replacement	Replacement Board Only	Replacement Cord Grips	Replacement Pressure & Condensation Vent	Desiccant Packs
JB4SS	88956	88958	58983=PG7 59001=PG11	88733 PreVent™ breather (vent) 88734 (vent nut)	92240
JB4ES	91779	89446	58983=PG7 59001=PG11	88733 PreVent™ breather (vent) 88734 (vent nut)	92240
JB4SP JB4SPT	91780 92762	88958 89894	58983=PG7 59001=PG11	88733 PreVent™ breather (vent) 88734 (vent nut)	16039
JB4EP JB4EPT	91781 92763	89446 89894	58983=PG7 59001=PG11	88733 PreVent™ breather (vent) 88734 (vent nut)	16039
EL204	73428	88958	N/A	N/A	N/A
JB8SP	91782 173807 - FM Approved	89889 172415 - FM Approved	15655 (cord grip) 15656 (nut)=3/8" NPT 15628 (cord grip) 15630 (nut)=1/2" SPT	88733 PreVent™ breather (vent) 88734 (vent nut)	16039
JB8SPT	91783	89889 (load cell) 89894 (transient protection)	15655 (cord grip) 15656 (nut)=3/8" NPT 15628 (cord grip) 15630 (nut)=1/2" SPT	88733 PreVent™ breather (vent) 88734 (vent nut)	16039
EL304A	21169	21301	N/A	N/A	N/A
JB1010	36231	36351	N/A	N/A	N/A
JB1010ST	68813	68811	N/A	N/A	N/A
EL210	91781, JB4EP*	92472	58983=PG7 59001=PG11	N/A	N/A
EL211A	91780, JB4SP* (The board does not have section trim capabilities)	92473 (The board does not have section trim capabilities)	58983=PG7 59001=PG11	N/A	N/A
EL604-AL	88956, JB4SS*	88958	58983=PG7 59001=PG11	N/A	N/A
EL604STA	88956, JB4SS*	88958	58983=PG7 59001=PG11	N/A	N/A
EL604ETA	91779, JB4ES*	89446	58983=PG7 59001=PG11	N/A	N/A
EL504	21165	21296	N/A	N/A	N/A
JB808S	91782, JB8SP*	92471	15655 (cord grip) 15656 (nut)=3/8" NPT 15628 (cord grip) 15630 (nut)=1/2" SPT	N/A	N/A
JB818ST	91783, JB8SPT*	Need (1) 77445, (1) 89889, (1) 89894	15655 (cord grip) 15656 (nut)=3/8" NPT 15628 (cord grip) 15630 (nut)=1/2" SPT	N/A	N/A

*See catalog page for enclosure dimensions

Part #	Description	List Price
91783	Signal Trim with Expansion, Polycarbonite Nema 4 w/transient protection	List Price: $700.00
89889	Signal Trim And Section Trim w/Expansion	List Price: $395.00
89894	Summing Box transient protection board	List Price: $235.00
165273	JB8SP/SPT Junction Box Enclosure W/O Cord Grips and filter. Incl Back plate, cover and gasket.	List Price: $175.00

Part #	Description	List Price
92734	Bonded, 1/2 in NPT Grip Cap To 92574 Coupling	List Price: $27.00
92735	Bonded, 3/8in NPT Cap To Coupling 92575	List Price: $27.00
215178	Mounting feet for new style JB4SP,JB4SPT,JB4EP,JB4EPT,JB8SP JB8SPT AND iQUBE enclosures. Set of 4 and includes 10-32 screws NOT for Hoffman enclosures	List Price: $15.00

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