On Feb 4, 11:44*am, cold ribs wrote:
Hi,

I have a spa outside my home. *It was installed by a certified
electrician, etc. *It used to trip the breaker on occasion (60amp, 2
pole), like if we left the high power jets on for 20 minutes or so. *No
big deal.

We just had the main CPU of the spa replaced and now it trips daily,
regardless of jet usage. *The guy who put in the new CPU said the
electrician who installed the spa initially used 8ga wire instead of
6ga, which he should have used.

Would this be the main reason for the tripping that used to occur on
occasion? *And, if so, why would it trip more frequently now?

HELP! *

I ran the no. 8 copper through with my online calculator and it says a
50 amp breaker is maximum and the continuous load is 40 amperes
maximum assuming using 90 degree C insulation on the wire and 75
degrees for the terminations.
With no other information NEC 110.14 says to use the 60 degree
termination rating and this gives a 40 ampere max breaker size and a
32 ampere maximum continuous load fro No. 8 copper.
For No. 6 copper with a 90 degree C insulation and a 60 degree C
termination a 60 ampere breaker is maximum for a 48 ampere continuous
load (three hours or more.)
Your breaker may be tripping because of over heating at the terminals
that is causing the breaker to over heat and trip.
The caculator is at: http://www.electrician2.com/calculat..._1_reverse.htm

REF:
110.14
(a) Termination provisions of equipment for circuits
rated 100 amperes or less, or marked for 14 AWG through
1 AWG conductors, shall be used only for one of the following:
(1) Conductors rated 60°C (140°F).
(2) Conductors with higher temperature ratings, provided the
ampacity of such conductors is determined based on the
60°C (140°F) ampacity of the conductor size used.
(3) Conductors with higher temperature ratings if the equipment
is listed and identified for use with such conductors.
(4) For motors marked with design letters B, C, or D, conductors
having an insulation rating of 75°C (167°F) or
higher shall be permitted to be used, provided the ampacity
of such conductors does not exceed the 75°C
(167°F) ampacity.