Curtis SP-600

Curtis SP-600

The Curtis SP-600 is a wall-mounted surge protector designed to plug directly into a duplex receptacle without the use of a power cord.

The documented example provides six grounded AC outlets and integrated coaxial-cable surge protection through dedicated IN and OUT connectors. Unlike many modern wall-mounted surge protectors, the SP-600 relies upon dual AC plug assemblies for mechanical retention and does not utilize the center faceplate screw commonly used by contemporary wall-hugger designs.

The documented example was purchased from Goodwill on 19 September 2026 for $5.00 and was subsequently preserved by the OldSurge Archive for documentation, testing, and analysis.

Curtis SP-600 wall-mounted surge protector documented by the OldSurge Archive.

Overview

Manufacturer	Curtis
Model	SP-600
Product Type	Wall-Mounted Surge Protector
AC Outlets	6
Coaxial Protection	Yes
Cord	None
Mounting Method	Dual Plug Assemblies
Country of Manufacture	Pending Documentation

Notable Characteristics

• First Curtis product documented by the OldSurge Archive.
• First wall-mounted surge protector documented by the archive.
• Six grounded AC outlets.
• Integrated coaxial surge protection with dedicated IN and OUT connectors.
• Dual-plug wall-hugger design.
• Does not utilize a center faceplate-retention screw.
• Riveted enclosure construction may require destructive techniques for internal examination.
• Purchased from Goodwill on 19 September 2026 for $5.00.
• Integrated coaxial surge protection with dedicated F-type IN and OUT connectors.
• Green protection-status indicator window.
• Dual-plug mounting system occupying both receptacles of a standard duplex outlet.
• Does not rely on a center faceplate-retention screw.
• Dual grounded plug assemblies occupy both receptacles of a standard duplex outlet.
• Riveted enclosure construction resists non-destructive disassembly.
• U.S. Design Patent DES. 350,937.
• Designed in the USA and manufactured in China.
• 400V TVSS ratings across all protection modes.

Specifications

• Manufacturer: Curtis
• Model: SP-600
• Product Type: Wall-Mounted Surge Protector
• AC Outlets: 6
• Coaxial Protection: Yes
• Coaxial Connectors: F-Type (IN / OUT)
• Cord Length: None
• Mounting Method: Direct wall receptacle connection

• Width: Approximately 3.38 in (8.6 cm)
• Height: Approximately 5.13 in (13.0 cm)
• Depth: Approximately 1.25 in (3.2 cm) excluding plug assemblies
• Manufacturer: Curtis
• Model: SP-600
• Product Type: Wall-Mounted Surge Protector

• AC Outlets: 6
• Coaxial Protection: Yes
• Coaxial Connectors: F-Type (IN / OUT)

• Width: Approximately 3.38 in (8.6 cm)
• Height: Approximately 5.13 in (13.0 cm)
• Depth: Approximately 1.25 in (3.2 cm) excluding plug assemblies

• Electrical Rating: 15A, 120VAC, 60Hz

• Maximum Suppression Rating: 400V Peak

• TVSS Ratings:
  • H-N: 400V
  • H-G: 400V
  • N-G: 400V

• UL File: E93801
• CSA File: LR83974

• U.S. Design Patent: DES. 350,937

• Country of Manufacture: China
• Designed In: USA

Weight

The documented example weighs approximately 6.7 oz (190 g).

The relatively light weight reflects the unit's compact wall-mounted design and absence of an attached power cord.

Curtis SP-600 wall-mounted surge protector on a digital scale showing a weight of approximately 6.7 oz (190 g).

Physical Characteristics

The Curtis SP-600 utilizes a molded plastic enclosure intended to plug directly into a standard duplex receptacle.

Six grounded outlets are arranged in two vertical rows of three receptacles each.

The lower portion of the enclosure incorporates coaxial-cable protection using standard threaded F-type connectors labeled IN and OUT.

Unlike most modern wall-mounted surge protectors, the SP-600 lacks a center mounting screw intended to secure the device to the receptacle. Mechanical retention instead relies on two sets of AC plug blades mounted on the rear of the enclosure.

The enclosure features curved ribbed side panels that project beyond the main housing and contribute to the unit's distinctive appearance.

A green indicator window is integrated into the upper portion of the enclosure and appears intended to provide surge-protection or operational-status indication.

The side portions of the enclosure incorporate prominent ribbed structures that project beyond the main outlet housing and give the device a distinctive appearance compared with later wall-mounted surge protectors.

The rear-mounted plug assemblies are distributed across both receptacle positions of a standard duplex outlet, allowing the device to derive mechanical support from two outlet connections rather than a single plug and center-retention screw.

The rear of the enclosure incorporates two complete grounded plug assemblies that occupy both receptacles of a standard duplex outlet.

Unlike most modern wall-mounted surge protectors, no provision is provided for securing the device using the center outlet-faceplate screw.

The enclosure appears to be assembled using metal rivets rather than screws. Complete disassembly would therefore require drilling or other destructive techniques to remove the rivets.

The documented example is marked with U.S. Design Patent DES. 350,937 and incorporates a green status-indicator window positioned near the top of the housing.

Unlike most modern wall-mounted surge protectors, the SP-600 utilizes two complete grounded plug assemblies and does not rely on a center faceplate-retention screw for support.

The enclosure is secured using metal rivets rather than screws. As a result, complete disassembly would require destructive techniques such as drilling the rivets.

The rear housing identifies the product as model SP-600, while the front of the enclosure is marked SP600.

The enclosure is marked with U.S. Design Patent DES. 350,937.

A molded "522" marking is present on the rear of the enclosure. The significance of this marking has not been determined and it may represent a mold identifier, production code, or manufacturing reference.

Photographs

• 
  Front view showing six grounded outlets and Curtis branding.
• 
  Integrated coaxial surge-protection connectors labeled IN and OUT.
• 
  Side profile showing wall-hugger construction and cosmetic paint flecks.
• 
  Opposite side profile showing wall-hugger construction and dual-plug mounting arrangement.
• 
  Top edge showing ribbed side structure and green protection-status indicator.
• 
  Curtis branding and upper outlet row detail.
• 
  SP-600 model designation and integrated coaxial protection section.
• 
  Rear view showing dual-plug mounting arrangement and riveted enclosure construction.
• 
  Data plate showing model information, electrical ratings, certifications, patent marking, and manufacturing details.
• 
  Lower rear detail showing one plug assembly, riveted enclosure construction, and molded markings.

Condition Upon Acquisition

The documented example exhibits light cosmetic wear consistent with normal residential use.

Accumulated dirt and minor staining were visible prior to cleaning. Small paint flecks were present on one side of the enclosure and minor scuffs and handling marks were observed throughout the housing.

No evidence of melting, cracking, overheating, or major physical damage was observed during external examination.

The unit was cleaned prior to detailed photography, testing, and documentation.

• 
  Condition upon acquisition prior to cleaning and documentation.

Overall condition is above average for a secondhand surge protector acquired through a thrift store.

Functional Testing

The documented example was connected to utility power and evaluated for basic functionality.

When energized, the green status indicator illuminated, indicating that the surge protector remained powered and operational at the time of testing. Illumination was present but noticeably dim.

Testing with a receptacle tester confirmed correct hot, neutral, and ground wiring. No open-ground, open-neutral, reversed-polarity, or other wiring faults were detected.

The documented example successfully passed basic functional testing and remained operational during documentation.

• 
  Curtis SP-600 connected to utility power during testing.
• 
  Close-up view of the illuminated green status indicator during testing.
• 
  Outlet tester indicating correct wiring and grounding.

Construction

Pending documentation.

Teardown

Pending documentation.

Collection History

The documented example was acquired by the OldSurge Archive in 2026 for preservation and documentation.

Documented Example

• OldSurge ID: OS-0020

Notes

• The front of the enclosure uses the model designation "SP 600" while the rear data plate identifies the product as SP-600.
• The green status indicator remained functional during testing but appeared noticeably dim.
• The device remained operational despite its apparent age.
• Correct outlet wiring and grounding were confirmed using a receptacle tester.

Related Articles

• Curtis
• Surge Protectors
• Collection Index