[RE-wrenches] down-sizing main breaker

[Kurt Albershardt]

On 8/1/09 11:08 , William Miller wrote:
> Our best solution would be to install a 200 amp meter panel with a 100 
> amp breaker.  The application is an agricultural based residence, so 
> based on how one interpreted this, the back feed allowance would be 
> either 100 amps or 120 amps, enough to cover our back feed.
>
> We were told by a supplier that we could purchase a 200 amp m/m/c and 
> field retrofit a 100 amp breaker into it.  We requested the supplier 
> contact the manufacturer (GE) and obtain confirmation of this claim.  
> We were assured that this was possible.
>
> Based on the assurances, we bid the job and won the contract.  When we 
> purchased the equipment we found that the 100 amp breaker could not 
> physically fit into the 200 amp m/m/c.  We spent a full day calling GE 
> and then other manufacturers only to find out that no one builds a 200 
> amp m/m/c that can fit a 100 amp main.  All of the panels we looked at 
> were cleverly configured to not allow the smaller breaker to be held 
> in place.
>
> Has anyone out there found a 200 amp m/m/c that can fit a 100 amp 
> main?  If so, I want to know.

Not yet, and I would also be quite interested as we have a green 
subdivision project in the wings which could use them.

I ran into a similar situation last year replacing an old 100A Zinsco 
panel.  I selected a 150A Siemens (which is really a relabeled 200A 
unit) for its 24 breaker spaces, leaving room for PV tie-in plus main 
panel surge suppression plus a little room for future expansion.  The 
utility was willing to allow a 125A service using the existing feeders, 
but refused to do 150A ("that's not a standard size for us") without 
upgrading quite a bit of overhead feeder.  We bought the 125A main kit 
for the same series of panel, only to find out what you did - that it 
does not mount in the 150A or 200A versions of the panel.  Because the 
customer has a pending underground service (future residence, which will 
supply the existing dwelling as a subpanel) they eventually agreed on a 
backfed Q2100H (even more expensive) for the interim overhead service.  
This was a separate meter application, not an all-in-one.




-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20090801/5ff20cb0/attachment-0004.html>