BoatHowTo · video

What this video covers

Stainless steel washers or bolts in a conducting path act as resistors under load, generating heat that can melt fuse holders, trigger thermal fuses, and destroy alternators.1:29 Nigel Calder explains that stainless steel is a poor conductor, so its presence in a live circuit creates resistance invisible to a voltmeter when the circuit carries no load — the voltage drop only appears under load.1:28 The danger escalates in high-current circuits: Calder cites multiple confirmed cases where stainless steel washers at ANL fuse holders transferred enough heat into the fuse to blow it thermally while alternators were running hard, destroying the alternators.2:01 The fix is straightforward — stainless steel fasteners are acceptable for clamping terminals mechanically, but copper or tinned-copper hardware must carry the current.1:16 Jan Attenstedt notes the topic is covered in the BoatHowTo BoatElectrics 101 course at BoatHowTo.com.2:30 Testing a suspect connection with a voltmeter only reveals the fault when the circuit is under load.0:49

More from BoatHowTo

Grounding on Aluminium Yachts 🔧 | Ask The Expert with NIGEL CALDERSept 2026Boat ELECTRIC PROPULSION with only LEAD ACID Batteries ?? | Ask The Expert with NIGEL CALDERSept 2026MaxProp: More Pitch in Reverse than in Forward? 🤔 | Ask The Expert with NIGEL CALDERSept 2026Common Ground Point with Isolated Saildrives | Ask The Expert with NIGEL CALDERSept 2026

From BoatHowTo — see the channel’s boat, crew, and every analysed video.

The Sailing Directory Newsletter

One email with the fleet's best finds — the moments, boats, and stories worth your watch time. Enter your own address to get your own copy.