SB 200 Breaker

[Ken Bakhaus]

Be careful with circuit breaker substitutions.  A 8amp breaker is not
necessarily equal to another 8 amp breaker. First of all there several
different types of  CBs - thermal, thermal with mag assist, magnetic and
magnetic with delay. Each of these have significantly different trip
response curves  which when used in the wrong application may not trip in
time or nuisance trip on transients. The maximum ultimate trip levels (the
overload current at which a device will trip within one hour, usually
somewhere between 120 and 150% of rating) varies considerably between types
and manufacturers and affects response. The trip temperature of thermal
types, which the SB200 CBs were, significantly effects and/or prevents
nuisance tripping as the ambient in the case increases. Other factors such
as overload and short circuit ratings vary between types and manufacturers.
Most of these low amp devices are really not circuit breakers by UL
definition but Supplementary Protectors covered by spec UL1077. There is a
lot of latitude allowed in the specs of devices which can qualify to this
standard.

I'm not saying the Tyco unit won't work but a lot more than amp rating is
involved in making a substitution. I know nothing about the type of the Tyco
unit or its specs so am just making an informative warning.

Ken K8PAO - since 59

----- Original Message -----
From: Mike Shelton <sheltonm at PHYSICS.UNC.EDU>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Monday, October 22, 2001 1:05 PM
Subject: SB 200 Breaker


> Newark shows a 8 amp breaker stock no. 57F276 made by Tyco Electronics
> page 534 catalog #118, price.............$5.43
>
> This should fit the application nicely.
> --
> Mike Shelton CET.
>    ke4lgx
> Electronic Technician III
> UNC-Chapel Hill
>
> -----------------------------------------------------------
> This list is a public service of the City of Tempe, Arizona
> -----------------------------------------------------------
>
> Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
> To post - HEATH at LISTSERV.TEMPE.GOV
> Archives - http://interactive.tempe.gov/archives/HEATH.html

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://interactive.tempe.gov/archives/HEATH.html