[RE-wrenches] Generator factory wiring issues

Thu May 26 08:26:25 PDT 2016

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 <KPegg at 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-bounces at lists.re-wrenches.org] *On
> Behalf Of *Daniel Young
> *Sent:* May-25-16 7:24 AM
> *To:* 'RE-wrenches' <re-wrenches at 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-bounces at lists.re-wrenches.org
> <re-wrenches-bounces at lists.re-wrenches.org>] *On Behalf Of *Kevin Pegg
> *Sent:* Tuesday, May 24, 2016 6:14 PM
> *To:* RE-wrenches <re-wrenches at 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,
>
>
>
>
>
>
>
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-- 
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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