Fast blow or time delay (anti surge) type? I have read motors require anti surge fuses to permit higher than rated current for short periods during start up.


1 Answer 1


You could use a slow-blow/anti surge/time delay. The heater's resistance is lower when cold, so there will be a surge of current as well (for a completely different physical reason). However, this depends on a particular application: coil temperature, thermal mass, wiring, what the critical current is.

  • \$\begingroup\$ Resistance of Nichrome it is not change significally with temperature. Temperature coefficient is only 0.4E-3/degrCelcius for nichr. Compare with copper coefficient 3.9E-3/degrCelcius. Heater is also pure ohmic load. \$\endgroup\$
    – GR Tech
    Commented Mar 31, 2015 at 17:28
  • \$\begingroup\$ Good point about nichrome, but let's if we take let's say 1000K vs 300K, the resistance change is about 30% using your value, which is not huge, but still something to consider. And thanks for the ohmic load info, captain :) \$\endgroup\$ Commented Mar 31, 2015 at 22:32

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