Portable generator wiring to transfer switch question

[SMF]

Hi,

Thanks for reading this. I'm hoping to get some advise about the wiring from my generator to my transfer switch - only partially done by my electrician a few years ago as I had not purchased a generator when he did the work.

My house is 100amps and he installed a transfer switch shown here which is a throw switch.

He then left me with a 20 foot black cord with the writing P-136-29-MSMA 12 AWG 4/G. On the invoice he describes this as 12/4 SJ cord.

Attached to this wire is a Nema L14-20 Levitron plug - same as the short run going to the transfer switch of which it connects to. On the invoice he describes these as 125/125 volt cord caps (one male and one female) (one end was left empty until I purchased a generator)

I ultimately purchased a honda generator EU6500. It calls for a cord cap with the specs L14-30P.

1. Can the required L14-30P cap work well attached to the wire and caps he left me as they do not sound like they match up?

1. Do I need to change the two other caps to 30 amps?

2. Is the wiring he gave me adequate for the 6500 generator and should I change that too?

I hope I was able to describe this well. Many thanks for your time!! Steve

[gfretwell]

The 20a plug will not fit the 30a receptacle on your generator. You need a L14-30 and 10 gauge wire..

[ransley]

Only if you dont load it can 12ga work, you can control the load with a transfer switch, mine has 10 ga, its all about managing load which has to be known to keep the gen lasting long

[mike]

switch.http://www.edwardssupply.com/product.php?productid=91128&cat=3142&page=2>>

While the above is true, depending on where you live and the local building codes, you may have some issues. Building codes are designed to make sure you NEVER overload anything. Your intention is irrelevant. ALL the wiring and connectors between the breaker and the load MUST be rated and approved by the relevant approval organization in your locale to handle the FULL capability of the breaker. It's one of those, "don't argue, just do it" areas. Your fire insurance underwriter may also care that your DIY wiring doesn't meet code.

Bottom line is that you need bigger wire and the proper connectors for a 30A generator. The additional cost is a small part of the total system cost. Better to be safe and legal and insured.

[trader4]

Agree with the above. If the cord has 10 gauge wire you can use it with a new 30A plug. If not, put it up on Ebay and get the correct one. Did the electrician ask what generator you were going to connect it to?

[SMF]

Thanks everybody for your replies!

Nope, he didn't know which generator I was getting as he did the work years ago. The recent hurricane got me buying one (that I may probably not need for years to come).

I am going to have him come and switch the wire to 10 and put on the right plugs. However he told that the insulation in these thicker wire gauges is different than house wire and it would work fine along with the 20A plugs and that I really don't need to do this. I'll have him switch anyway for my peace of mind.

[bud--]

The NEC gives the current rating for 3 current carrying conductors #12 SJ as 20A. It is OK for the 20A plug. If your generator has the appropriate protected 20A receptacle you can use the cord. If you want to use the full capacity of the generator you need a 30A plug and cord.