You power welding rigs and inspection gear by sizing diesel generators to the nameplate input of each machine, plus the lighting, tools, and support loads that share the same supply. The right number depends on the welding process, the equipment your contractor brings, and how the spread is laid out on site. Stag Power Rentals supplies diesel generators from 20 kW to 2000 kW out of its Dickinson, TX yard, so the fleet can cover a single welding station or a larger group of loads. This page covers the equipment side of the question, while the broader field setup is handled on our pipeline spread logistics page.
Welding output is not the only thing that draws power, because inspection gear, grinders, lighting, and small tools often share the same supply. Cable and ground return rules also shape how machines connect to a generator. OSHA 1926.351 says arc welding and cutting cables must be completely insulated, flexible, and capable of handling the maximum current requirements, and that a ground return cable must carry at least the maximum output capacity of the unit it serves. The same standard states that pipelines containing gases or flammable liquids shall not be used as a ground return. Confirm the details with your safety lead, since this page does not replace your site rules.
What Loads Sit on a Pipeline Welding Spread
Every spread assigns power differently, and your contractor’s equipment list is the starting point. Engine-driven welders carry their own power, while electric-drive or inverter-based welding machines draw from a generator or distribution panel. Inspection crews add their own equipment, which is usually smaller than a welding rig but can be sensitive to poor power quality. Treat the list below as categories to check against your equipment specifications, not as a complete inventory.
- Electric welding power sources and wire feeders
- Grinders, beveling tools, and pipe preparation equipment
- Preheat equipment, where the weld procedure calls for it
- Inspection equipment such as nondestructive testing gear and its support lighting
- Work lighting for night or low-light shifts
- Site office, tool trailer, and charging loads
How the Welding Process Changes Sizing
The welding process matters because different processes and machines pull different input power, and the data plate is the only dependable figure. Some machines list input amps at a specific voltage and phase, while others list kVA. A generator also has to handle the starting surge and the cycling load that welding produces, so a continuous rating alone does not settle the fit. The table below organizes the questions to settle with your welding contractor before you choose a unit.
| Load | What drives the demand | Confirm before sizing |
|---|---|---|
| Electric-drive welding machines | Nameplate input at the rated output and the process in use | Input voltage, phase, and amps or kVA from the data plate |
| Wire-feed or multi-process machines | Process, output setting, and duty cycle | Which procedures run at the same time |
| Grinders and prep tools | Motor starting current | How many run alongside the welders |
| Inspection gear | Equipment list from the inspection vendor | Voltage requirement and whether it needs a dedicated circuit |
| Lighting | Fixture type and count | Whether shifts run after dark |
| Preheat | Method named in the weld procedure | Whether the procedure requires it at all |
Once the table is filled in, add the figures to a load list, using the construction site generator sizing guide for the method. The amperage chart for industrial generators helps you check what a generator can deliver in amps at your voltage. Keep a margin above the calculated total, and ask your contractor how much margin they want. Stag can review the list and suggest a unit, though the contractor should verify the final selection.
Where to Place Generators Along the Right-of-Way
Placement balances cable length against exposure to the work. A generator near the welding stations shortens the cable run, but it also puts a running engine close to people and fuel. Fire prevention rules apply around welding, so keep generators and fuel storage where your safety plan allows. Trailer-mounted units are a common option on linear jobs because they move with the crew, and Stag covers that option on its towable diesel generator rental page.
Inspection stations are often fixed for a stretch and then move forward, which can favor a smaller dedicated generator over long cable runs from a welding unit. Separating inspection power from the welding supply can also keep welding load swings away from sensitive equipment. Ask the inspection vendor about their power quality requirements before you decide. Inspection and testing gear at a drilling crossing is covered in the article on what powers a directional drilling crossing.
Distributing Power to Each Station
Distribution connects one generator to several stations, and it deserves its own plan. Stag offers power distribution equipment to split a supply across loads, so cable and panels are not improvised in the field. The sequence below is a general way to plan it, and your electrician or safety lead has the final say.
- List every station and its load.
- Group stations by location along the spread.
- Assign each group to a generator or panel.
- Check cable and ground return capacity for each welding unit against its rated output.
- Decide who moves the equipment as the crew advances.
Shift Schedules and Run Time
Stag bills diesel generator rentals by single, double, or triple shift, so your crew’s working hours shape the rental structure. Welding crews that run long days or add a night shift may need lighting and inspection power after dark. Fuel use depends on the load and the unit, and the manufacturer data for the selected model is the place to check it. Tell the team your shift plan up front so the quote reflects it.
Bring Your Welding Equipment List to Stag
Stag Power Rentals can match diesel generators to a welding and inspection equipment list from its Dickinson, TX yard. Send the data plates, shift plan, and site details, and the team will work through sizing with you. Browse our construction industry overview for related equipment, or send the details through the quote request form. A short list of loads gives the team what it needs to respond.
Frequently Asked Questions
Do welding rigs run directly off a generator?
Some welding machines are engine-driven and carry their own power, while others take input power from a generator or panel. Check the data plate on each machine to see which applies. If the machine takes input power, size the generator to that nameplate input and the other loads on the same supply. Confirm the details with your welding contractor.
How do I size a generator for several welding stations?
Start by listing each machine with its nameplate input voltage, phase, and amps. Add the inspection, lighting, and tool loads that share the supply. Account for motor starting and cycling welding loads, then add a margin agreed with your contractor. Stag can review the list and recommend a unit from the 20 kW to 2000 kW fleet.
Should inspection equipment share the welding generator?
It depends on the equipment and the site. Welding loads cycle and can affect sensitive gear, so some crews give inspection its own supply. Ask the inspection vendor about power requirements before deciding. Your site safety plan may also set rules on where each unit sits.
How are rentals billed for a job that runs long days?
Stag bills by single, double, or triple shift. The category that fits depends on how many shifts your crew works. Share your schedule when you request a quote so the team can match it. Contract terms are confirmed in the quote itself.
Can the generator move as the welding crew advances?
Trailer-mounted units are built for moving between locations, and Stag offers towable options. Whether a specific unit suits your route depends on the terrain, the tow vehicle, and the contract. Tell the team how often you expect to relocate. Your contractor decides who handles the moves.