Are all banana plugs the same? Can I use these Fluke brand banana plugs and plug them in to this Extech brand phase rotation tester? Will they fit?

Picture of fluke banana plug test leads, captured from Fluke website

Picture of Extech phase rotation tester, captured from Extech website

What defines banana plugs anyway? Is there an ISO standard or something?

MSC Direct has a better picture of the phase rotation tester that makes it look to me like it uses standard "banana" connections.

enter image description here

But what really IS the standard for banana connections, and how can I be sure that my banana fits into the banana hole?

  • \$\begingroup\$ Test equipment stuff will probably all mix and match without problems. \$\endgroup\$
    – user57037
    Aug 2, 2020 at 7:23
  • \$\begingroup\$ Just for added info banana plugs as pairs are normally have 750 mil centers. Banana plugs are used world-wide so enjoy common dimensions. Note that extra sleeving for DVMs may keep them from being used in common banana panel jacks. As for actual standards, they would be easy to Google... \$\endgroup\$
    – user105652
    Aug 2, 2020 at 8:00
  • \$\begingroup\$ @VTNCaGNtdDVNalUy I have also seen them located with a hard metric spacing of 19mm (close enough) but also 20mm. \$\endgroup\$ Aug 2, 2020 at 13:20
  • \$\begingroup\$ @SpehroPefhany My conversion program shows 19.05mm = 0.748", and 20mm = 0.787". Though not perfect I have been able to interchange them. \$\endgroup\$
    – user105652
    Aug 2, 2020 at 19:53
  • \$\begingroup\$ I thank you all for the inputs. I also have never had a problem with banana plug compatibility. But on the other hand when I am about to do a formal purchase request that will take about 6 months to fulfill, and I'm spending about $1000 because I need multiple test kits, I like to be able to connect all of the dots and verify that parts will fit. Or else I look like a real Bozo. \$\endgroup\$ Aug 4, 2020 at 5:06

2 Answers 2


The actual connector part will fit without problems - a 4mm banana connector always fits the same across all vendors.

Unfortunately the plastic protection is not standardized - I experience problems every now and then. Either the plastic is too long or the thicker part of the connector starts too early or the tiny plastic cap in the middle of the banana plug just got stuck in the socket. Some devices only accept straight connectors as well.

TL/DR: Impossible to say without actually trying it.

  • \$\begingroup\$ My conversion program shows 19.05mm = 0.748", and 20mm = 0.787". Though not perfect I have been able to interchange them. In USA we see them as being 750 mils apart. Good enough to work in most cases. \$\endgroup\$
    – user105652
    Aug 3, 2020 at 6:49
  • \$\begingroup\$ @VTNCaGNtdDVNalUy Where did you get a measurement of 20mm from? This is about 4mm thick banana plugs. \$\endgroup\$
    – asdfex
    Aug 3, 2020 at 9:16
  • \$\begingroup\$ That is the pin to pin spacing for dual banana plugs which are very common. \$\endgroup\$
    – user105652
    Aug 3, 2020 at 22:26
  • \$\begingroup\$ Your TL/DR summary matches my experience, but I can't afford to just try it. With a 6 month procurement process, and I need to order enough equipment to build 5 test kits, I need to get it right the first time. \$\endgroup\$ Aug 4, 2020 at 5:08

They're all the same 4mm diameter banana hole same diameter shroud and a compatible springy pin.

For a phase sequence meter choosing plugs with a shroud that's deep enough to fully protect the pin is probably important.

  • \$\begingroup\$ Is there a governing standard for the banana plugs? That might really help me out here. I need to get it right the first time. Thank you! \$\endgroup\$ Aug 4, 2020 at 5:09
  • \$\begingroup\$ The standards are usually American and the TROTW which is metric \$\endgroup\$ Aug 22, 2020 at 18:51

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