Heat Trace Start Up current
Heat Trace Start Up current
(OP)
Hi Guys,
Can anyone provide me the formula for calculating the 'start up' current for heat tracing?
If I have normal heater operating amps 18.5 A, How would I determine the 'start up' current?
Thanks.
Can anyone provide me the formula for calculating the 'start up' current for heat tracing?
If I have normal heater operating amps 18.5 A, How would I determine the 'start up' current?
Thanks.






RE: Heat Trace Start Up current
RE: Heat Trace Start Up current
All I know is the CB should be sized based on ambient temperature (which is -20) in my case. This is based on the fact that the heater will draw more current as the temperature drops.
RE: Heat Trace Start Up current
Keith Cress
kcress - http://www.flaminsystems.com
RE: Heat Trace Start Up current
Let me put it this way. The normal operating current(at ambient temperature) is 18.5Amps.
But if the heater is to START at -20 degree centrigrade, the heater would require more current then the normal current. I would like to know that 'starting current'. Any factors or formule for this?
RE: Heat Trace Start Up current
Keith Cress
kcress - http://www.flaminsystems.com
RE: Heat Trace Start Up current
Are you trying to figure out operating cost, or are you trying to size breakers?
RE: Heat Trace Start Up current
Mineral insulated?
Straight resistive?
Start up current of heat trace is all over the map, depending on the expected ambient and the type of heat trace.
You need to find the manufacture's literature. Google often helps.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Heat Trace Start Up current
I'm using self regulating cables but it really doesn't matter much what kind of cable you are using to determine the circuit breaker size. The method for determining the 'start up' current should be the same if you know the normal operating current and the lowest ambient temperature.
Ykee, I'm trying to size the breaker, which should be based on the start up current. And the start up current is based on the lowest ambient temperature which is negative 20 centigrade in my case.
RE: Heat Trace Start Up current
RE: Heat Trace Start Up current
Even say it is 3 times the rated current, if you select a 30A CB (based on 18.4A), the breaker will not trip on 60A for several seconds. After all heater is not a motor.
Any breaker sized for 1.25% of the rated current or one size larger (of you are in doubt) would suffice. For higher rated breaker you need to select the conductors accordingly.
For anything more definitive you need to consult the mfr. as advised before.
RE: Heat Trace Start Up current
GOOGLE THE MANUFACTURER'S SITE.
In some installations the trace is strapped to a large heat sink. that is a large, cold steel pipe full of cold product. The heater may take enough time to come up to temperature that the breaker may have to withstand "cold current" for some time.
Check the spec's!!
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Heat Trace Start Up current