[RE-wrenches] Generator factory wiring issues

Wed May 25 22:23:22 EDT 2016

UL evaluates products on internal temperature rises while it is used=20
normally.

They also evaluate the products under abnormal use, in various ways.

It may or may not have a fan.  If you look inside an inverter, you will=20
see the same type of

things....  Large external battery cables connecting to smaller internal=20
cables and/or

bus-bars and circuit board traces.  All sorts of things that probably=20
are not allowed

with NEC.

I think I  saw a temperature of 150 degrees F mentioned here. That's nothing

compared to the highest temperatures seen in certain parts of the products.

Some wire, like in some transformer classes can reach as high as 220=20
degrees C (428 F) !

boB

On 5/25/2016 11:39 AM, Kevin Pegg wrote:
>
> Hi Daniel,
>
> Appreciate your thoughts on this.
>
> - This wire is contained inside 2" flexible metallic conduit, approx.=20
> 3' long from the alternator to the external breaker. Some of it is in=20
> 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=20
> full load, and my expectations is all the wiring in that unit is=20
> suited to that. Will the site actually draw that? It is entirely=20
> possible during heavy loads & concurrent battery charging that it=20
> 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=20
> tells me that the #4 wire is undersized. So there is a dilemma. If I=20
> replace the wires myself then I believe I have voided the UL=20
> certification. But think have made a safer engine for my client. At=20
> the end of the day, it will be me who the client is calling if there=20
> is an issue.
>
> Just for kicks I opened up a couple 25 kW gens and factory wiring was=20
> either # 2 or # 4 for this same purpose. Hmm.
>
> Kevin
>
> *From:*RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org]=20
> *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=20
> table 310.15(B)(19). It=E2=80=99s rated for 120A when in conduit. So is t=
his=20
> wire where you might call it in conduit or free air? I imagine the=20
> inside of a generator enclosure is somewhere in the middle. Also I=20
> assume this is Z type or similar based on the response stating 150 F=20
> (I know he meant C) wiring is used.
>
> Is this on a 175A breaker? If so then it should only pull 140A=20
> continuous (maybe it=E2=80=99s a 100% rated breaker?). And that really wo=
uld=20
> not be great for a generator. Usually we only design for a maximum of=20
> 80% loading on a generator depending on elevation and a few other=20
> de-rate factors. In reality do you expect more than 120A to be a true=20
> =E2=80=9Ccontinuous=E2=80=9D load on this unit. I don=E2=80=99t know the =
answer, just worth=20
> thinking about.
>
> Plastic bushings:
>
> I sure would want them in a vibrating machine like a generator, but if=20
> UL does not force them to, don=E2=80=99t expect them to include it.=20
> (Capitalism at work). You might be able to use an electricians trick=20
> where you cut a PVC bushing and slip it over the existing wire, then=20
> you can thread it in the end of the fitting and it is 95% as good as a=20
> normally installed bushing=E2=80=A6. I would not do it on a new install, =
but=20
> it=E2=80=99s a useful trick when you walk up on existing mistakes.
>
> Lug:
>
> You could continuity test it to see if it=E2=80=99s a good connection,=20
> otherwise that strikes me as no good either. Just another cost saving=20
> step for the manu at the clients expense in my opinion. It=E2=80=99ll wor=
k=20
> fine for now, but not likely in 5-10yrs as corrosion sets in. I=E2=80=99d=
 just=20
> throw a star washer underneath if possible, but it sounds like the=20
> stud is not long enough.
>
> So there is a little bitta=E2=80=99 code and a lotta=E2=80=99 opinion.
>
> With Regards,
>
> Daniel Young,
>
> NABCEP Certified PV Installation Professional^TM : Cert #031508-90
>
> *From:*RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org]=20
> *On Behalf Of *Kevin Pegg
> *Sent:* Tuesday, May 24, 2016 6:14 PM
> *To:* RE-wrenches <re-wrenches at lists.re-wrenches.org=20
> <mailto: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=20
> are outlined in detail below, with an engineer's response inline. The=20
> concerns are using #4 wire to pull 175A; no plastic bushings on=20
> metallic conduit, and ground lugs on top of painted surfaces / and=20
> insufficiently torqued.
>
> The engineer response has left me somewhat baffled / frustrated in=20
> that I do not feel that actual issues have been addressed. I don't=20
> really care what UL or any other authority tells me - pulling 175A=20
> continually for many hrs through a #4 wire I think is asking for=20
> trouble. And my customer won't really care about what the UL ratings=20
> 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=20
> designer and as U.L. liaison.
>
> We have received this generator, mostly intact. Some freight damage to=20
> the battery support cross member due to forks not extending the full=20
> depth of the crate, and are working with the freight company to=20
> resolve that.
>
> Sorry for the experienced freight damage.
>
> However, there are some SERIOUS and DANGEROUS issues pertaining to the=20
> wiring of the alternator! It is obvious that wiring was not done by an=20
> electrician.
>
> There are no serious or dangerous issues on this (built to U.L.=20
> recognized spec) Gillette Generator as referred to in this writing.=20
> And =E2=80=93 you are correct- this wiring, as =E2=80=98factory wiring an=
d not =E2=80=98field=E2=80=99=20
> wiring, does not require or use the specific qualifications of a=20
> licensed electrician. The well trained/supervised workers here at=20
> Gillette have many years of experience building the product and are=20
> guided as need by a competent engineering staff.
>
> Specifically:
>
> - Alternator to circuit breaker wiring was done with #4 wire (rated=20
> 60A max). Per your own load chart inside the breaker enclosure (photo=20
> attached), that wire should be 4/0 to carry the 175A that this=20
> generator is capable of producing.
>
> This observation is incorrect. The load wiring sizing schedule affixed=20
> to the side of the circuit breaker box is for =E2=80=98field connectivity=
=E2=80=99 at=20
> 75 deg. F. We do our =E2=80=98factory wiring =E2=80=98 on a different sch=
edule using=20
> load cabling from the generator to the top of the circuit breaker=20
> rated at 150 deg. F. All of this cabling has been done, tested and=20
> proven by U.L
>
> - There were no plastic bushings (see photo) where the wires exit the=20
> metal conduit.
>
> The conduit bushing involved is the correct U.L. approved component=20
> for the installation of spiral wound metal conduit required to be=20
> installed on =E2=80=98open=E2=80=99 style generator assemblies. A plastic=
 bushing is=20
> NOT required as this is again =E2=80=98factory wiring=E2=80=99, not =E2=
=80=98field wiring.
>
> - What would have happened here is the wire heats up due to gross=20
> under sizing, melts the insulation, and shorts it out. Resulting in a=20
> fire or destruction of the brand new alternator, and the associated=20
> legal proceedings involving all parties and a general nightmare for=20
> all of us.
>
>  disagree, on several fronts. Referencing the specification standard=20
> U.L. 2200, many times- local inspectors blur the line between its=20
> dominance for standby generator systems and NEC-70 (NEC- code). The=20
> former covers =E2=80=98factory=E2=80=99 design wiring on stationary stand=
by generators=20
> subject to witness testing by a U.L. certified representative. The=20
> latter applies to =E2=80=98field wiring=E2=80=99- that is anything outsid=
e the box=20
> including connection conduits, load wiring ( at 75 deg. F) transfer=20
> switches, distribution panes and the like. As resident designer for=20
> the past twenty-six years, I have myself- written eight standards/code=20
> rebuttals successfully, both for U.L. and local inspectors. Comparing=20
> a 4ga, 2ga, 1ga and the like against a different class of wiring such=20
> as a 4/0 would certainly be cause for alarm. But, clearly here_the=20
> alarm is unwarranted_.
>
>                 - the ground lug on the alternator was not fastened=20
> properly (a short stud with a nut on it - no way to get proper torque=20
> on it - should be a bolt), and both this lug and the lug inside the=20
> breaker enclosure was fitted on top of a painted surface. Every=20
> electrician knows you need to scrape off the paint so as to allow for=20
> proper conductivity.
>
> This lug is not supplied by us. It is supplied as part of the=20
> generator construction built by Marathon. Marathon generators are=20
> certified for U.L. 1004B- generator assemblies and U.L. 1446 for=20
> insulation. This is the equipment issued as part of that U.L.=20
> certified design. as to their design vs. a =E2=80=98bolt=E2=80=99 going i=
nto the=20
> threads of the hole-  if it was really an issue, it would not have=20
> passed their U.L. certification testing. Their generator assemblies=20
> bear their U.L. file certification under R/C (JZGZ2) and listing=20
> (JZGZ). In regards to the paint removal, the engine and generator are=20
> cable grounded to the frame of the generator assembly and serrated=20
> hardware is used during assembly to scratch into the painted surfaces=20
> of the boxes and frame. As you notice in the picture- the threads in=20
> the generator housing sleeve- are not painted.
>
>                 These are issues that we are able to remedy. But my=20
> client, being very hands on has noticed this and inquired, quite=20
> reasonably, as to why they are paying Energy Alternatives to repair=20
> something that they paid for and should have been delivered properly=20
> 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=20
> remedy these defects and to have Collicutt reimburse use for time and=20
> materials. I will complete the work and send you the total bill for=20
> compensation unless you would like to approach this in a different=20
> method. We are hoping to go live with this unit in the next few days=20
> 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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