Philips 37688-9 C400S51/2 400W E39 HPS Instant Restrike

Product Overview

Philips 37688-9 C400S51/2 — 400W Ceramalux Instant Restrike High Pressure Sodium Lamp, E39 Mogul Base

The Philips 37688-9 C400S51/2 is a 400W Ceramalux Instant Restrike High Pressure Sodium (HPS) lamp from Philips Lighting, built with a dual arc-tube design for roadway, warehouse, and security lighting where a power interruption cannot mean extended darkness. With an E39 Mogul Screw base, ED18 bulb shape, ANSI code S51, and universal burn position, this lamp delivers 49,000 initial lumens and a 24,000+ hour rated life. Verify wattage, ANSI code, base type, and ballast compatibility before ordering — HPS lamps require an HPS-rated ballast and ignitor.

Wattage

400W

HPS / HID

Lumens

49,000 lm

Initial Output

Color Temp

2100K

Warm Amber

Base

E39

Mogul Screw

Rated Life

24,000+ hrs

Average Life

Technical Specifications

SKU	PHLB376889
Brand	Philips Lighting
Philips Product Number	37688-9
Series	Philips Ceramalux Instant Restrike — High Pressure Sodium
Lamp Type	High Pressure Sodium (HPS) — Instant Restrike, Dual Arc Tube
Ordering Code	C400S51/2
Bulb Shape	ED18
Wattage	400W
Initial Lumens	49,000 lm
Mean Lumens	44,000 lm
CRI	~21
Color Temperature	2100K Warm Amber
Base Type	E39 Mogul Screw
ANSI Code	S51
Burn / Operating Position	Universal
LCL (Light Center Length)	5¾″
MOL (Max Overall Length)	9¾″
Rated Average Life	24,000+ hours (Instant Restrike mode)
Standard Package Quantity	12 per case
UPC / EAN	Not listed — confirm with Philips/Signify before ordering

Product Overview

The Philips 37688-9 C400S51/2 is a Ceramalux Instant Restrike HPS lamp built around an extra arc tube: if the primary arc tube is interrupted by a power dip, the second arc tube provides light instantly, and the lamp returns to 80% light output within 1–2 minutes — instead of the 5–15 minute cool-down and restrike delay of a standard single-arc-tube HPS lamp. At 400W, it delivers 49,000 initial lumens (44,000 mean lumens at 40% of rated life), suited to roadway, warehouse, and security lighting where continuous illumination through momentary outages matters.

The ED18 bulb shape and E39 Mogul Screw base make this a direct replacement in fixtures previously housing a standard 400W HPS lamp with ANSI code S51. Universal burn position allows installation in any orientation. The lamp operates on standard HPS ballasts and auxiliary equipment — no special ballast is required for the instant restrike function. Rated average life is 24,000+ hours in instant-restrike service; Philips notes a 40,000-hour rated average life is achievable for applications where instant restrike is not required. This lamp contains sodium and mercury and must be recycled per applicable regulations.

Not recommended for: retail displays, color-critical inspection environments, sports venues, or any application requiring CRI above ~21.

Compatible Applications

Roadway and street lighting — Where instant restrike after a power dip is a safety requirement.
Warehouse and industrial high-bay — Facilities where extended blackouts from lamp restrike delays are unacceptable.
Security and perimeter lighting — Parking lots, yards, and outdoor areas requiring continuous illumination.
Retrofit and maintenance replacement — Direct replacement for existing 400W HPS lamps with E39 base and S51 ANSI code. Verify ballast compatibility before ordering.

Before Ordering — Verify

ANSI / Lamp Code: Confirm the existing lamp or equipment manual matches S51.
Wattage: Confirm the fixture is rated for 400W.
Base Type: Confirm the socket matches E39 Mogul Screw.
Ballast Compatibility: This lamp requires an HPS-rated ballast and ignitor. It operates on standard HPS ballasts and auxiliary equipment; it will not operate on a Metal Halide or Mercury Vapor ballast.
Burn Position: Fixture supports Universal operation — no restriction.
Physical Fit: Confirm ED18 bulb shape, LCL 5¾″, MOL 9¾″, and fixture clearance against the existing lamp or fixture manual.
UPC/EAN: Not listed on the manufacturer datasheet used for this rebuild — confirm with Philips/Signify or your distributor before publishing barcode data.

Safety and Handling Guidelines

Correct Ballast Required: Use only with an HPS-compatible ballast and ignitor rated for this lamp. Using an incompatible ballast can result in lamp failure or fixture damage.
High-Pressure Arc Tube: HPS lamps operate under high internal pressure. Always use appropriate eye protection when handling or replacing lamps. Allow lamps to cool fully before removal.
Fixture Design: Do not use this lamp in a fixture that redirects a substantial portion of energy toward the arc tube and its immediate vicinity, as this may lead to early lamp failure.
Approved Fixtures Only: Install only in fixtures rated for the listed lamp type, wattage, and operating position. The fixture wattage rating must match the wattage on the outer glass bulb.
Handling: Do not scratch the outer bulb or subject it to pressure — this could cause the outer bulb to crack or shatter. Replace the lamp if the outer glass bulb has been scratched, cracked, or damaged in any way.
If Broken: If the outer glass bulb is broken, shut off power immediately and remove the lamp after it has cooled. If the arc tube is broken, avoid skin contact with its contents or fragments.
Mercury Content: Contains sodium and mercury. Do not dispose of in regular trash. Recycle through an approved lamp recycling program in accordance with federal, state, and local regulations.

Compliance

Contains sodium and mercury — subject to applicable lamp recycling and disposal regulations. California, Washington, and other states may have mandatory take-back or handling fee requirements.
Verify RoHS compliance status, UL listing, Title 20, and Prop 65 requirements with the Philips manufacturer specification sheet prior to use in regulated installations.