I would find a way to load test the generator, let it run under load for four hours. If nothing breaks, you don't need to do anything.
On Wed, May 25, 2016 at 2:39 PM, Kevin Pegg <kp...@energyalternatives.ca> wrote: > Hi Daniel, > > > > Appreciate your thoughts on this. > > > > - This wire is contained inside 2" flexible metallic conduit, approx. 3' > long from the alternator to the external breaker. Some of it is in free > air, but most is contained within the conduit. > > - the main breaker is a 100% rated 175A. > > - This is an industrial generator is rated for continual operation at full > load, and my expectations is all the wiring in that unit is suited to that. > Will the site actually draw that? It is entirely possible during heavy > loads & concurrent battery charging that it could well be running at max > load for hrs at a time. > > > > The plastic bushing is easy to remedy, as is the ground lug. > > > > The wire is where I am not sure what to do. Everything I am hearing tells > me that the #4 wire is undersized. So there is a dilemma. If I replace the > wires myself then I believe I have voided the UL certification. But think > have made a safer engine for my client. At the end of the day, it will be > me who the client is calling if there is an issue. > > > > Just for kicks I opened up a couple 25 kW gens and factory wiring was > either # 2 or # 4 for this same purpose. Hmm. > > > > Kevin > > > > *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On > Behalf Of *Daniel Young > *Sent:* May-25-16 7:24 AM > *To:* 'RE-wrenches' <re-wrenches@lists.re-wrenches.org> > *Subject:* Re: [RE-wrenches] Generator factory wiring issues > > > > Kevin, > > > > Based on what the engineer said, I think you both make valid points. > > > > On the 4AWG wire: > > > > Type Z wire (150 C insulation) is rated for 190A based on 2014NEC table > 310.15(B)(19). It’s rated for 120A when in conduit. So is this wire where > you might call it in conduit or free air? I imagine the inside of a > generator enclosure is somewhere in the middle. Also I assume this is Z > type or similar based on the response stating 150 F (I know he meant C) > wiring is used. > > > > Is this on a 175A breaker? If so then it should only pull 140A continuous > (maybe it’s a 100% rated breaker?). And that really would not be great for > a generator. Usually we only design for a maximum of 80% loading on a > generator depending on elevation and a few other de-rate factors. In > reality do you expect more than 120A to be a true “continuous” load on this > unit. I don’t know the answer, just worth thinking about. > > > > Plastic bushings: > > > > I sure would want them in a vibrating machine like a generator, but if UL > does not force them to, don’t expect them to include it. (Capitalism at > work). You might be able to use an electricians trick where you cut a PVC > bushing and slip it over the existing wire, then you can thread it in the > end of the fitting and it is 95% as good as a normally installed bushing…. > I would not do it on a new install, but it’s a useful trick when you walk > up on existing mistakes. > > > > Lug: > > > > You could continuity test it to see if it’s a good connection, otherwise > that strikes me as no good either. Just another cost saving step for the > manu at the clients expense in my opinion. It’ll work fine for now, but not > likely in 5-10yrs as corrosion sets in. I’d just throw a star washer > underneath if possible, but it sounds like the stud is not long enough. > > > > So there is a little bitta’ code and a lotta’ opinion. > > > > With Regards, > > > > Daniel Young, > > NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90 > > > > *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org > <re-wrenches-boun...@lists.re-wrenches.org>] *On Behalf Of *Kevin Pegg > *Sent:* Tuesday, May 24, 2016 6:14 PM > *To:* RE-wrenches <re-wrenches@lists.re-wrenches.org> > *Subject:* [RE-wrenches] Generator factory wiring issues > > > > Wrenches, > > > > Recently, we took delivery of a 40 kW LPG generator made by Gillette. > > > > Inspecting the factory wiring of the unit, I had some concerns which are > outlined in detail below, with an engineer's response inline. The concerns > are using #4 wire to pull 175A; no plastic bushings on metallic conduit, > and ground lugs on top of painted surfaces / and insufficiently torqued. > > > > The engineer response has left me somewhat baffled / frustrated in that I > do not feel that actual issues have been addressed. I don't really care > what UL or any other authority tells me - pulling 175A continually for many > hrs through a #4 wire I think is asking for trouble. And my customer won't > really care about what the UL ratings say if they are dealing with a melted > alternator. > > > > Am I missing something here? > > > > Kevin > > > > > > RE: SP-410-1-1LO S/N: > > > > I am responding to the concerns written below both in the capacity as > designer and as U.L. liaison. > > > > We have received this generator, mostly intact. Some freight damage to the > battery support cross member due to forks not extending the full depth of > the crate, and are working with the freight company to resolve that. > > Sorry for the experienced freight damage. > > > > However, there are some SERIOUS and DANGEROUS issues pertaining to the > wiring of the alternator! It is obvious that wiring was not done by an > electrician. > > There are no serious or dangerous issues on this (built to U.L. recognized > spec) Gillette Generator as referred to in this writing. And – you are > correct- this wiring, as ‘factory wiring and not ‘field’ wiring, does not > require or use the specific qualifications of a licensed electrician. The > well trained/supervised workers here at Gillette have many years of > experience building the product and are guided as need by a competent > engineering staff. > > > > Specifically: > > > > - Alternator to circuit breaker wiring was done with #4 wire (rated 60A > max). Per your own load chart inside the breaker enclosure (photo > attached), that wire should be 4/0 to carry the 175A that this generator is > capable of producing. > > This observation is incorrect. The load wiring sizing schedule affixed to > the side of the circuit breaker box is for ‘field connectivity’ at 75 deg. > F. We do our ‘factory wiring ‘ on a different schedule using load cabling > from the generator to the top of the circuit breaker rated at 150 deg. F. > All of this cabling has been done, tested and proven by U.L > > > > - There were no plastic bushings (see photo) where the wires exit the > metal conduit. > > The conduit bushing involved is the correct U.L. approved component for > the installation of spiral wound metal conduit required to be installed on > ‘open’ style generator assemblies. A plastic bushing is NOT required as > this is again ‘factory wiring’, not ‘field wiring. > > > > - What would have happened here is the wire heats up due to gross under > sizing, melts the insulation, and shorts it out. Resulting in a fire or > destruction of the brand new alternator, and the associated legal > proceedings involving all parties and a general nightmare for all of us. > > disagree, on several fronts. Referencing the specification standard U.L. > 2200, many times- local inspectors blur the line between its dominance for > standby generator systems and NEC-70 (NEC- code). The former covers > ‘factory’ design wiring on stationary standby generators subject to witness > testing by a U.L. certified representative. The latter applies to ‘field > wiring’- that is anything outside the box including connection conduits, > load wiring ( at 75 deg. F) transfer switches, distribution panes and the > like. As resident designer for the past twenty-six years, I have myself- > written eight standards/code rebuttals successfully, both for U.L. and > local inspectors. Comparing a 4ga, 2ga, 1ga and the like against a > different class of wiring such as a 4/0 would certainly be cause for alarm. > But, clearly here *the alarm is unwarranted*. > > > > - the ground lug on the alternator was not fastened > properly (a short stud with a nut on it - no way to get proper torque on it > - should be a bolt), and both this lug and the lug inside the breaker > enclosure was fitted on top of a painted surface. Every electrician knows > you need to scrape off the paint so as to allow for proper conductivity. > > This lug is not supplied by us. It is supplied as part of the generator > construction built by Marathon. Marathon generators are certified for U.L. > 1004B- generator assemblies and U.L. 1446 for insulation. This is the > equipment issued as part of that U.L. certified design. as to their design > vs. a ‘bolt’ going into the threads of the hole- if it was really an > issue, it would not have passed their U.L. certification testing. Their > generator assemblies bear their U.L. file certification under R/C (JZGZ2) > and listing (JZGZ). In regards to the paint removal, the engine and > generator are cable grounded to the frame of the generator assembly and > serrated hardware is used during assembly to scratch into the painted > surfaces of the boxes and frame. As you notice in the picture- the threads > in the generator housing sleeve- are not painted. > > > > These are issues that we are able to remedy. But my > client, being very hands on has noticed this and inquired, quite > reasonably, as to why they are paying Energy Alternatives to repair > something that they paid for and should have been delivered properly done > in the first place? > > To my findings, there is no warrantable work required. > > > > I think the fairest solution to this is for us to remedy > these defects and to have Collicutt reimburse use for time and materials. I > will complete the work and send you the total bill for compensation unless > you would like to approach this in a different method. We are hoping to go > live with this unit in the next few days once the gas fitting is completed. > > As stated above- Not required. > > > > I hope these responses help clarify the items in question. > > > > > > Regards, > > > > > > > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > > -- Chris Mason NABCEP Certified Solar PV Installer™ Solar Design Engineer Generac Generators Industrial technician www.cometsolar.com <http://www.cometenergysystems.com> 264.235.5670 869.662.5670 Skype: netconcepts
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