PO Box 581

Wauna, WA  98395

Phone: 1-253-884-4008

Fax: 1-253-884-5064

Email: sales@proglassinc.com

Secondary Splice Boxes with Overlapping Lid

Superior strength, lightweight, and durable

Available in green or gray gel-coated finish, our secondary splice boxes offer a superior strength, lightweight and durable field product.

Fiberglass secondary splice boxes are easily installed and  are available with a matching lid. Optional threaded inserts provide added security.


ProGlass manufactures the finest fiberglass electrical boxes in the industry.  Our commitment to excellence guarantees you will install a satisfactory product - every time. Give us a call today and let’s get started: 1-253-884-4008.

ProGlass Secondary Splice Boxes:


▪ High Strength-to-Weight Ratio and  Internal Reinforced Ribs: When quality and durability matter, our superior strength won't let you down.


▪ Easy Storage: Compact size, generally tapered for nesting, reducing storage yard requirements.

▪ Non-conductive and Corrosion Resistant:
Fiberglass construction prevents conductivity of electrical currents, eliminates the need for grounding, and offers a fire-resistant finish.

▪ Non-skid Surface:
Each lid is made with a super non-skid diamond-patterned surface.

▪ Added Security: Penta-head bolts offer additional protection against tampering.


▪ Balanced: A perimeter lip at the base provides added stability.

Sizing Chart: Secondary Splice Boxes

Optional Lid

Looking for another size?

If you don't see the size you need listed here, just give us a call: 1-253-884-4008

View .PDF on

ProGlass, Inc. Secondary Splice Boxes

Questions? Ready to place your order?

Email us at: sales@proglassinc.com or call


PO Box 581, Wauna, WA  98395

Phone: 1-253-884-4008

Fax: 1-253-884-5064

Email: sales@proglassinc.com


All Rights Reserved

Copyright © 1990-2019 ProGlass, Inc.

Power Glass, Inc. DBA ProGlass, Inc.

Made in USA

NOTICE: This document (and all of the information, data and designs contained herein) is the property of Power Glass, Inc. DBA ProGlass, Inc. AKA ProGlass, and is to be used only in reference to work proposed or contracted by PROGLASS. This confidential information must not be copied, duplicated, or used without the expressed permission or written consent of PROGLASS. Dimensions (inches) are measured at the intersection of projected adjacent places.