Wire THNN or XHHW?

[Catbird]

I'm installing a Lewmar Pro 1000 windlass. The manufacturer specifies 6 AWG cable for the length I need to run.

I've just encountered new terminology for 6 AWG insulation: THNN or XHHW. The Lewmar tech support tech I've spoken with was not familiar with either designation. Is anyone knowledgeable about choosing either THNN or XHHW? Thanks.

 

[wpc691]

Not a pro (I’m sure someone will chime in), but I believe that’s ordinary UL44 construction cable, not marine wire to UL1426. HXXW-2 is superior to THNN, and is available tinned, but probably still isn’t the right stuff. Check with an ABYC electrician.

 

[ksanders]

THHN and XHHW describe insulation. THHN is thin, X wire is thick insulation. THHN is generally used in a raceway or conduit. X wire is often used in semi open installations in controlled, limited entry areas. We use X wire in substation contrl houses for example, where the wire is exposed but the entire building is limited entry by qualified persons.

Either standard THHN or X wire will probably be really large size conductors and difficult to bend.

Marine grade cable is similar to welding wire in that it is much smaller conductors and easier to bend around things on a boat.

My boat, I would opt for the marine grade romex style cable with both conductors in a separate jacket for a windlass.

 

[DavidM]

HXXW has a higher heat range than THHN, but does it matter? With proper fusing and wire sizing you will stay well within the parameters of both.


Also not sure that ABYC specifies either. I suspect that they say to size the wire and fuse it to stay within the wire's heat rating. I also know that most wire sizing calculators are based on THHN wire's 105 deg C heat rating.


Theoretically you could use a smaller size XHHW wire as it can pass more current without exceeding its heat rating, but then you will have too much voltage drop. Voltage drop almost always results in a larger size wire than insulation rating does.


Genuinedealz.com is where I buy my tinned marine wire. Their wire meets ABYC and USCG requirements.


David

 

[STB]

I think ABYC 11.14.2.1.1 requires either UL 1426 or, in certain cases, SAE J378.

The construction of this type of wire is fairly complex, with variables including the metal used for the condutors, the number of conductors, the thickness of the conductors, how they are bundled, whether or not they are tinned, and the material and thickness of the insulation, etc, as well as differences in the units used for wire gauge (SAE vs AWG).

Using wires the wrong stuff can make it harder to pull, more susceptible to damage while pulling, more likely to corrode, more likely to crack with vibration, more likely to get water into it, less able to handle the current, less able to handle routine and overload heat, etc.

I think ABYC (E-11, 11.14.2.1.1) guidelines generally call for UL 1426, but allow for certain SAE ratings in certain circumstances.

Personally...the scariest thing for me is a fire in a small boat. If it was me -- I'd go for the "good stuff".

 

[Catbird]

I'm going to use 4 AWG Gauge Battery Cable Tinned Copper Marine Wire
@ 1.72/ft from Genuinedealz.com.


Many thanks for responding.

 

[twistedtree]

I'm going to use 4 AWG Gauge Battery Cable Tinned Copper Marine Wire
@ 1.72/ft from Genuinedealz.com.


Many thanks for responding.

Good choice!

 

[Delta4242]

Good choice! The THHN wire is not to be used in marine environments. At the least, it has a higher resistivity than what you're using and would result in a high voltage drop thus poor windlass performance.

 

[FF]

"I'm going to use 4 AWG Gauge Battery Cable Tinned Copper Marine Wire
@ 1.72/ft from Genuinedealz.com."

While weight is seldom a problem in trawlers , cost can be.

If the billfold can stand it going with thicker wire is usually a good choice.

Use copper nuts and bolts for assembly , not SS for best results.

google will show many sources

 

[Shrew]

Also worth noting that the guage is based on amperage and the length of the entire round trip from battery to device and back to battery again.

Lewmar 1000 shows a current draw of 50amps (12v). This would put your circuit at around 20-25 feet. Are the batteries only 12 feet from the windlass?

https://www.lewmar.com/sites/defaul...s/Pro-series-fish-manual-G3_B10490 iss2_0.pdf

12 Volt - Wire Gauge vs. Amps


4G wiring:
-> 60-70amps @ 15 ft
-> 50-70amps @ 20 ft
-> 40-50amps @ 25 ft
-> 30-40amps @ 30ft
-> 25-30amps @ 40ft
-> 20-25amps @ 50 ft
-> 20 amps @ 60ft
-> 15 amps @ 70-80 ft
-> 10-15amps @ 90ft

 

[Catbird]

The run from the windlass to the battery is approximately 22 feet. Lewmar calls for 6 awg. I'm using a 4 awg cable from the windlass to the battery - and - a second 4 awg cable from the battery back to the windlass. OK - right?
​

 

[PMF1984]

That’s a run of 44 feet. Look up on the internet a table of wire sizes based on amps and distance. You have to learn how to do this if you are doing any wiring.

 

[twistedtree]

That’s a run of 44 feet. Look up on the internet a table of wire sizes based on amps and distance. You have to learn how to do this if you are doing any wiring.

You will also be considering how much voltage loss is acceptable for the device. Typically you will find tables for 3% loss which is used for electronics, and 10% loss for most other things. Your windlass is probably fine with 10% loss, though less is always better, at a cost. The manual may say what loss is acceptable.