1910.255(b): Spot and Seam Welder Safeguards
Employers must run external weld initiating control circuits on spot and seam welders at low voltage, not over 120 volts. High-voltage capacitor equipment (over 550 volts) needs insulated full enclosures with interlocks that cut power and short all capacitors when opened, plus a manual discharge switch. Doors and panels must be locked and interlocked, press welding points of operation guarded, moving parts guarded, and flying sparks shielded wherever practical.
Key takeaways
- 1910.255(b) is part of OSHA's general industry standards (29 CFR Part 1910, Subpart Q).
- OSHA cited it 25 times in the last 3 years, in 21 inspections, with $134,789 in current penalties.
- Most citations: WI (6), OH (6), TN (3).
- Related part: 1910.255(b)(4) Guarding (19 citations).
- Free 5-minute toolbox talk for your crew below.
In this article
What this rule covers
29 CFR 1910.255(b) ("Spot and seam welding machines (nonportable)") is one requirement inside 1910.255 Resistance welding, an OSHA general industry standard (Part 1910, Subpart Q). It includes 9 sub-paragraphs. The official text below is copied word for word from the Electronic Code of Federal Regulations (eCFR). The numbers, injury cases and training on this page show how OSHA enforces it on real job sites.
Official text
(b) Spot and seam welding machines (nonportable) — 25 citations
(1) Voltage. All external weld initiating control circuits shall operate on low voltage, not over 120 volts, for the safety of the operators. 1 citations
(2) Capacitor welding. Stored energy or capacitor discharge type of resistance welding equipment and control panels involving high voltage (over 550 volts) shall be suitably insulated and protected by complete enclosures, all doors of which shall be provided with suitable interlocks and contacts wired into the control circuit (similar to elevator interlocks). Such interlocks or contacts shall be so designed as to effectively interrupt power and short circuit all capacitors when the door or panel is open. A manually operated switch or suitable positive device shall be installed, in addition to the mechanical interlocks or contacts, as an added safety measure assuring absolute discharge of all capacitors.
(3) Interlocks. All doors and access panels of all resistance welding machines and control panels shall be kept locked and interlocked to prevent access, by unauthorized persons, to live portions of the equipment.
(4) Guarding. All press welding machine operations, where there is a possibility of the operator's fingers being under the point of operation, shall be effectively guarded by the use of a device such as an electronic eye safety circuit, two hand controls or protection similar to that prescribed for punch press operation, § 1910.217 of this part. All chains, gears, operating bus linkage, and belts shall be protected by adequate guards, in accordance with § 1910.219 of this part. Open (b)(4) 19 citations
(5) Shields. The hazard of flying sparks shall be, wherever practical, eliminated by installing a shield guard of safety glass or suitable fire-resistant plastic at the point of operation. Additional shields or curtains shall be installed as necessary to protect passing persons from flying sparks. (See § 1910.252(b)(2)(i)(C) of this part.) 4 citations
(6) Foot switches. All foot switches shall be guarded to prevent accidental operation of the machine. 1 citations
(7) Stop buttons. Two or more safety emergency stop buttons shall be provided on all special multispot welding machines, including 2-post and 4-post weld presses.
(8) Safety pins. On large machines, four safety pins with plugs and receptacles (one in each corner) shall be provided so that when safety pins are removed and inserted in the ram or platen, the press becomes inoperative.
(9) Grounding. Where technically practical, the secondary of all welding transformers used in multispot, projection and seam welding machines shall be grounded. This may be done by permanently grounding one side of the welding secondary current circuit. Where not technically practical, a center tapped grounding reactor connected across the secondary or the use of a safety disconnect switch in conjunction with the welding control are acceptable alternates. Safety disconnect shall be arranged to open both sides of the line when welding current is not present.
Source: eCFR, text current as of 2026-10-15. Read all of 1910.255.
Where and how often it was cited
| Year | Citations |
|---|---|
| 2024 | 10 |
| 2025 | 11 |
| 2026 | 4 |
Top states: WI (6), OH (6), TN (3), IL (2), CT (2)
Largest penalties
| Employer | Location | Penalty for this rule |
|---|---|---|
| TOPRE AMERICA CORPORATION | SPRINGFIELD, OH | $16,550 |
| CLARK RELIANCE LLC | STRONGSVILLE, OH | $14,518 |
| EBM-PAPST INC. | FARMINGTON, CT | $13,240 |
| LIST INDUSTRIES, INC. | DEERFIELD BEACH, FL | $12,905 |
| DEFIANCE METAL PRODUCTS | DEFIANCE, OH | $11,823 |
Free toolbox talk
A 5-minute crew talk on 1910.255(b), plus alerts when this rule changes. Free.
OSHA interpretation letters
None exist. OSHA has not published a letter of interpretation for 1910.255(b).
Related parts of this rule
- 1910.255(b)(4) Guarding 19 citations
Get your crew competent
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Frequently asked questions
What voltage is allowed for control circuits?
Not over 120 volts.
How must press welding points of operation be guarded?
By a device such as an electronic eye safety circuit, two hand controls or protection similar to punch press rules in 1910.217.
How are flying sparks controlled?
Wherever practical, by a shield guard of safety glass or suitable fire-resistant plastic at the point of operation.
About this page
Sources
- 29 CFR 1910.255 (eCFR), text current as of 2026-10-15
- U.S. Department of Labor enforcement data: OSHA inspections, citations and accident records, copied nightly; data as of 2026-10-23
3-year window. Federal OSHA only; state-plan rules are not counted. Plain-language text is a summary, not legal advice; the official text controls. Black Belt Safety is not part of OSHA or the Department of Labor.