Updated May 16 2017
Blade fuse problems in caravans include fuses and fuse holders burning or melting. Fire risk is high because the fuses may continue to conduct. Ongoing current flow, however, may heat the fuse holder to burning point. This article by Caravan and Motorhome Books explains why and how to overcome the risk.
Blade fuse problems in caravans – fuse holder sizes
There are two main sizes of blade fuses and blade fuse holders. Most blade fuse problems in caravans arise if the smaller size fuses and fuse holders are used at currents greater than 15 amps. Some auto-electricians suggest 10 amps. All need protecting against damp or salty water, or atmospheres.
As can be seen, the larger size has substantially more contact area.
Blade fuse problems in caravans – quality issues
There can also be blade fuse problems in caravans with poor quality versions of the larger sizes fuses and holders. Some have next to no protection against even mild corrosion. This causes them to resist current flow, usually partially melting the holder but not necessarily the fuse. This results in a major risk of fire – especially if the wiring’s insulation is also burned. It may expose current carrying copper that, then allows full battery current to flow – possibly to earth. This can and does cause fires.
Blade fuse problems in caravans – the need for larger holders
Blade fuse problems in caravans – circuit breakers preferred
Ideally, replace high current blade fuse holders and fuse by manually re-settable dc circuit breakers. Those of totally reliable quality are stocked by marine electrical suppliers. Cheaper versions are available but are very temperature sensitive. This, in particular, is not an area to cut costs via eBay specials.
This a high quality double pole dc circuit breaker. It protects both positive and negative cables. Pic: Carling Inc.
See also Circuit-Breakers-and-Fuses-in-RVs
Blade fuse problems in caravans – further information
Every aspect of RV electrics is covered in detail in my Caravan & Motorhome Electrics. Solar That Really Works is for cabins and RVs. Solar Success is for homes and properties. My other books are the Camper Trailer Book and the Caravan & Motorhome Book. For info more about the author Click on Bio.
Please post a LINK to this article on forums if you feel it would assist problems in this area.