LEONI cable and harness orders: 7 mistakes I made so you don't have to

I've spent—or rather, I've wasted—enough money on custom cable and wire harnesses over the past eight years to buy a small car. A good chunk of that waste involved LEONI. I don't say that proudly. I say it because I now maintain the pre-order checklist that keeps our team from repeating my mistakes.

Here are the questions I ask myself now. If you're about to order LEONI cable, connectors, or a wiring system, read them before you hit send.

• “Leoni mini dress product info and reviews” and LEONI cable: same company?
• Should I contact LEONI Kerpen directly?
• What was my costliest LEONI mistake?
• Why isn't the lowest quote the cheapest?
• Does a blood pressure monitor need special cable treatment?
• How much detail does an RFQ need?
• What's on the final pre-order checklist?

1. Wait, “Leoni mini dress product info and reviews”? That doesn't sound like cable.

That's a different Leoni, or at least it's not the LEONI division I order from. If you're looking for dress product info and reviews, this FAQ is the wrong page.

The LEONI in our supplier system makes wires, cables, connectors, fiber-optic products and complete wiring systems. Search engines don't always separate brands with similar names. I can't help with the dress. If you're here because a cable order has LEONI on the drawing, keep going.

2. Should I email LEONI Kerpen for a quote?

Not as your first move. LEONI Kerpen is a real site in our supplier records, and my contact there answers emails. But LEONI has several product groups and plants. I emailed Kerpen in my second year because the name showed up in a search result. It took five days to learn that the product line I needed was handled by another division.

It works better to send the RFQ to your LEONI sales rep or the official inquiry address. If someone has already told you the part is associated with Kerpen, put “LEONI Kerpen” in the RFQ notes. Let the quotation team route it to the right place.

3. What was the LEONI mistake that still hurts?

The 450-piece cable order with wrong connector orientation. It looked perfect on my screen. LEONI built exactly what the drawing in my RFQ said. The drawing was wrong—pin 2 and pin 3 were swapped.

Every unit went to rework. The extra freight and labor came to around $3,400. Actually, $3,412. I looked at the PO ledger last year.

The part that still bugs me: I had the thought “I should double-check the connector drawing” two hours after I sent the PO. I didn't call to stop it. Now, if a “wait, I'm not sure” thought appears, I stop and ask before I send anything.

4. So the lowest quote isn't the cheapest?

Not for custom cable, in my experience. I don't have hard data on the whole industry. But I have our own small set: 22 quote comparisons over five years. In 8 of those 22, the lowest initial quote was not the lowest total cost by the time we added tooling, freight, inspection, extra downtime and rework.

If you're buying a standard catalog item, price matters more. For a custom LEONI harness, total cost matters more. “It's cheaper on the quote” only applies if the quoted product will arrive on time and work the first time.

5. Does a cable for a blood pressure monitor need special treatment?

Usually, yes. A blood pressure monitor isn't a passive display device; it can be a medical device that touches a patient. That changes the questions you need to ask before you buy.

In 2023, I learned this the boring way: our cable passed electrical tests but the documentation failed a review. We didn't hide anything. We just wrote “cable assembly” on the RFQ when we should have written “cable assembly for a medical device (blood pressure monitor).” The difference cost us about $1,800 in rework and a delay.

The LEONI team didn't cause it. The missing end-use info caused it. If the customer's legal name is something like “Blood Pressure Monitor, Inc.”, that should be enough to trigger medical-device questions—even when the cable seems simple.

6. How much detail does an RFQ need?

More than most people send. I know, writing an RFQ is not fun. I once spent 45 minutes reading “best shaver” comparison posts and then sent a harness RFQ in about ten minutes. The harness lacked one environmental requirement, and it failed in the field.

A shaver purchase affects one person. A harness purchase affects a production schedule and a customer shipment. At minimum, spend as much time on the RFQ as you did on your last “best shaver” search.

7. What is on your pre-order checklist now?

Here is the version I use before any custom LEONI cable or harness PO:

• Part number and revision level from the drawing, not just “same as last time.”
• Connector type, orientation, pin mapping, and mating part number.
• Wire gauge, insulation, color code, length, and bend/flex requirements.
• Operating temperature, voltage, current, and anything the cable touches.
• Industry or medical standards that apply, including country-specific markings.
• Correct LEONI entity or plant if the product history references one, e.g. LEONI Kerpen.
• Delivery date written as an actual date, not “the week after a holiday.”
• Who reviews the prototype or routing sample, and what exactly they must check.

I still kick myself for the $3,400 connector order. But if you're reading this at 10 pm before a morning PO, that checklist is the reason our buyers don't repeat that particular mistake.