[RE-wrenches] 690.8

[Ray Walters]

The exception under 690.8(B)(1) definitely applies.  All of Midnite' 
breakers and boxes are rated for 100% continuous operation.  I believe, 
this does not apply to their touch safe fuse assemblies, however.  Also 
FYI,  you should be able to use the 90 deg C rating for complying with 
110.14 (C) at least for the terminals in Midnite's combiner.  (This is 
according to my conversations with Midnite)

Also, it seems that you might be exceeding the max fuse rating of the 
modules.   You might want to check that.  Why not have each series 
string on its own 15 amp breaker?

R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760

On 11/9/2016 6:57 PM, Jerry Shafer wrote:
> Wrenches
> We are getting some questions from PRMD some questions relating to 
> 690.8 here is what we have
> 3 modules, 260 watts at 9 amps ISC each module is a single string which
> goes into a MNPV6 disco/combiner/disconnect
> combined to a 30 amp breaker, it is being replaced with a 40 amp per 
> 690.8(A) 1
> leaves there and goes to a 32 amp disconnect in our device.
> here is where it gets interesting
> 690.8 (A) requires the 40 amp breaker but reading down to 690.8 (B) 1 we
> need to up-size to 50 amps (no 45 amp is non available)
> We also have added the 63 amp GFI in the disco
> we have also moved up from # 10 wire to # 8 wire as a result
> All this seams over kill for three modules, there are 2 exceptions but 
> PRMD do
> not feel they are relative.
> Is the Midnite solar disco considered an assembly with the bus bars 
> inside if we install the breakers
> Any ideas would be helpful
> Jerry
>
>
>
>
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