Let'sgoflying!
Touchdown! Greaser!
What is the theory behind the mobile home 4th wire, why is it needed?
[NA]mobile home service feeds[NA]
- Thread starter Let'sgoflying!
- Start date
denverpilot
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From everything I've read, it's because the box containing the disconnect and the main service panel are separated.
If there's a ground fault, the neutral in the disconnect box isn't bonded to ground inside and it can make the box itself live, making the disconnect box the most dangerous place to touch, ironically.
So the disconnect and the main panel have to be bonded together since the neutral/ground bond happens in the panel in the mobile home.
Googling around, some states allow a three wire feed if other ways to bond the disconnect and the mobile home panel are accomplished. And/or allow grandfathering.
I am definitely not an electrician so maybe one will wander by. But it basically looks like it's because there's often up to 30' between the main disconnect and the main panel. So you need belt and suspenders to make sure you don't create a hot case at the disconnect.
If there's a ground fault, the neutral in the disconnect box isn't bonded to ground inside and it can make the box itself live, making the disconnect box the most dangerous place to touch, ironically.
So the disconnect and the main panel have to be bonded together since the neutral/ground bond happens in the panel in the mobile home.
Googling around, some states allow a three wire feed if other ways to bond the disconnect and the mobile home panel are accomplished. And/or allow grandfathering.
I am definitely not an electrician so maybe one will wander by. But it basically looks like it's because there's often up to 30' between the main disconnect and the main panel. So you need belt and suspenders to make sure you don't create a hot case at the disconnect.
Let'sgoflying!
Touchdown! Greaser!
hmm, the mobile home I am looking at, the main disco is going to be separated from the distribution panel - but so is my home and business ie they are exactly the same.
But the sketches I am finding show the neutral bonded to ground in the disconnect box -- and by design they are separated in the distribution panel.
(not to be argumentative; just seeking "Mobile Home Electrical Truth"
)Thanks
denverpilot
Tied Down
hmm, the mobile home I am looking at, the main disco is going to be separated from the distribution panel - but so is my home and business ie they are exactly the same.
But the sketches I am finding show the neutral bonded to ground in the disconnect box -- and by design they are separated in the distribution panel.
(not to be argumentative; just seeking "Mobile Home Electrical Truth"
Thanks
Yeah I'd ask a sparky on this one. Looks like "mobile" and "manufactured" also force a completely different set of rules in many places, too.