Custom GPT: Build a Field Code Reference for Line Workers

What This Builds

Instead of carrying multiple code binders or calling the office to look up OSHA minimum approach distances, grounding requirements, or NESC clearances, you'll have a Custom GPT on your phone that answers these questions instantly — configured with your company's specific context, so it knows your voltage classes and equipment types. Instead of 10-15 minutes searching through PDFs, you get an answer in 30 seconds.

Prerequisites

• ChatGPT Plus subscription ($20/month)
• Comfortable using ChatGPT for at least 1-2 weeks (Level 3)
• Access to key reference documents in PDF format (OSHA 1910.269 summary, company safety standards, NESC reference sheets — ask your safety department)
• Cost: Included in ChatGPT Plus subscription

The Concept

A Custom GPT is like having a new coworker who has already read every safety manual, code book, and procedure document you gave them — and is standing by to answer questions any time you need. You configure it once with the documents and instructions, and then every conversation starts from that shared knowledge. It's different from the regular ChatGPT because it always knows it's talking to a lineworker and always references your specific documents first.

Build It Step by Step

Part 1: Gather your reference documents (30 min)

Collect these documents in PDF form. Check your company intranet, ask your safety department, or download from government sources:

1. OSHA 1910.269 Appendix B — Minimum Approach Distances table (free from osha.gov)
2. Your company's PPE/rubber goods requirements — if you have a field safety manual PDF
3. Your company's switching and tagging procedures summary — key steps for clearances
4. NESC clearance tables (if your utility has a summary sheet)
5. Any state-specific electrical safety codes that apply to your work

If you can't get all of these, start with what you have. The Custom GPT will still be useful with partial documentation — it will just be clear about what it found in your documents versus general knowledge.

Part 2: Create the Custom GPT (20-30 min)

1. Go to chat.openai.com on a computer (this step works better on desktop)

2. Click Explore GPTs in the left sidebar

3. Click Create a GPT (top right)

4. You'll see two panels: Configure (left) and Preview (right)

5. In the Name field, type: Line Worker Field Reference

6. In the Description field, type: OSHA, NESC, and company code reference for journeyman lineworkers. Answers questions about minimum approach distances, PPE requirements, grounding procedures, and switching standards.

7. In the Instructions box, paste this system instruction:

You are a field code reference assistant for journeyman lineworkers in electric power distribution.

Your role: Answer questions about OSHA 1910.269, NESC clearances, PPE requirements, grounding procedures, and company switching standards.

Rules:
1. Always check uploaded knowledge files first. If the answer is in the files, reference the exact document and section.
2. If the answer is NOT in the uploaded files, answer from your general training knowledge about OSHA 1910.269 and utility safety standards, and clearly label it as "General Knowledge (verify with published source)."
3. Never make up safety requirements. If uncertain, say so and recommend verifying with the published standard or operations center.
4. Keep answers brief and practical — one clear answer, then the key details. No lengthy explanations unless the user asks.
5. Always note if a safety decision requires formal clearance or supervisor approval.
6. The user is a journeyman lineworker. Use standard utility field terminology.

1. Under Knowledge, click Upload files and upload your collected PDFs one by one.

2. Under Capabilities, enable: Code Interpreter (off), DALL-E (off), Web browsing (optional — turn on if you want it to look up current OSHA pages)

Part 3: Test and Refine (15-20 min)

In the Preview panel on the right, test these questions:

Test 1: "What are the OSHA minimum approach distances for a qualified worker on a 12.47kV energized line?"

Expected: Specific distance from the MAD table, reference to OSHA 1910.269 Appendix B, note about phase-to-ground vs. phase-to-phase.

Test 2: "What PPE is required for switching a 12kV recloser?"

Expected: Reference to your uploaded PPE document (if uploaded), or general OSHA guidance labeled as such.

Test 3: "Is arc flash PPE required for this voltage class?"

Expected: Answer from your documents or general OSHA knowledge, clearly labeled.

If answers seem wrong or too vague, click Edit GPT and refine your instructions. Common fixes:

• Add "Always start your answer with the specific requirement in bold" for cleaner formatting
• Add "The utility operates at voltages from 4kV to 34.5kV" to help it contextualize voltage questions

Real Example: Full Workflow

Setup: You uploaded OSHA 1910.269 Appendix B (the MAD table) and your company's PPE standard.

Input: You're at the job site, about to do a transformer changeout. The work order says 12.47kV. You open your phone and ask:

Output:

Time saved: 12 minutes of binder-flipping reduced to 15 seconds.

Setup: The MAD answer was from the uploaded OSHA document. The PPE answer was from your company's PDF. Clear sourcing, no guessing.

What to Do When It Breaks

• "I don't see that in my uploaded documents" → The document may not have been processed correctly. Try re-uploading. Or ask "Answer from your general knowledge and label it."
• Wrong distance given → Check if you specified phase-to-ground voltage or phase-to-phase. Ask again specifying "7200V phase-to-ground (12.47kV three-phase system)"
• GPT not accessible on mobile → The Custom GPT lives at a URL you can bookmark. Find it in "My GPTs" on desktop, then open that URL on your phone and bookmark it.
• Documents outdated → Delete old files and re-upload updated versions. The GPT immediately uses the new documents.

Variations

• Simpler version: Skip the Custom GPT and just use regular ChatGPT with your documents uploaded in a Claude Project (see Level 3 guide). Less setup, slightly more manual.
• Extended version: Add your state's utility commission safety rules, your utility's grounding standard, and specific equipment manuals for transformers and reclosers you work with most.

What to Do Next

• This week: Build the GPT, test it on 5 real questions from your last 3 jobs
• This month: Share the concept (not the GPT itself — your company docs are in it) with your safety steward; they may want a crew-wide version
• Advanced: Add equipment-specific manuals (transformer installation guides, recloser specs) to expand what it knows

Advanced guide for journeyman lineworker professionals. ChatGPT Plus ($20/mo) required. Always verify safety-critical information against published OSHA standards and company procedures before acting.