replace transfer switch with 50amp plug?

[hertfordnc]

I have a friend who's on some hard times and living in an older HR pusher in a park.

It sounds like his transfer switch has croaked. For a while he would lose power from the pole and it would only run on generator.

Then it stopped getting power from either source.

He really does not have $150-200 for a new switch.

My suggestion is that he wire it the way my much older coach is wired,

The AC cord goes to the breaker panel. The generator goes to a female 30 amp plug. Instead of a transfer switch i plug the RV cord into the plug to operate from the generator.

I am a fair electrician but i have not been out ot see just what htis would entail

Any thoughts or opinions would be appreciated.


thanks

[garry1p]

Transfer switches have what is called "break before make" relays to prevent from ever having two sources connected at any given time.

An arc can occur when the relay disconnects from its source with appliances turned on. Over time this corrodes/pits the contacts and enough resistance occurs preventing enough current to pass or weld the contacts together so they cannot disconnect.

The relay contacts can be cleaned with 400 grit sandpaper but this is a temporary solution and eventually you will have to replace the contacts or the transfer switch.

[MrWizard]

30 amp transfer switches are either/or , and usually default is shore power
Without the switch being energized
With generator on the relay energizes and connects to generator
In this situation the generator will act as an override and attempt to disconnect from shore power, this is how people fry the generator and appliances in 30 amp rigs

50 amp the transfer switch often has (2) relays one for each the generator and shore power, and in some cases a mechanical lock out is included between the relays, so when one is active the other cannot engage
Our Safari DP came with this type of transfer switch

[Bumpyroad]

larry cad wrote:

No, not true. My son's first motorhome had a manual transfer switch. It had a knob mounted on the outside of the box that you could use to switch between shore and genny power.

so on your son's MH he could connect two sources of power to the rv at once? didn't the "switch" automatically switch sources when the kob was moved?
bumpy

[wolfe10]

Yup, three options:

ATS

Manual transfer switch-- very common in marine applications

Female plug for generator, so manually plug shore power cord in for generator power.

[DrewE]

larry cad wrote:

Bumpyroad wrote:

I thought transfer switches were all "automatic"? the other option is just to move the plug to a different outlet mechanically and is not a transfer switch.
bumpy

No, not true. My son's first motorhome had a manual transfer switch. It had a knob mounted on the outside of the box that you could use to switch between shore and genny power.

Very often transfer switches for backup generators for houses are also manual. It's a normal-ish switch; you flip it in one direction for utility power, and the other direction for generator power, and sometimes there might be a setting in the middle for no power.

For whatever reason, manual transfer switches are not at all common in (modern) RVs.

[larry_cad]

Bumpyroad wrote:

larry cad wrote:

Tom/Barb wrote:

AllegroD wrote:
The Automatic Transfer Switches, in an RV, are generally generator priority.

ours isn't, if you are running equipment on the get-set, then plug into 50 amp service the 50 amp service will accept the load, and relieve the get-set.

Thus the name, "AUTOMATIC transfer switch"

🙂

I thought transfer switches were all "automatic"? the other option is just to move the plug to a different outlet mechanically and is not a transfer switch.
bumpy

No, not true. My son's first motorhome had a manual transfer switch. It had a knob mounted on the outside of the box that you could use to switch between shore and genny power.

[hertfordnc]

wolfe10 wrote:
Someone safe working around 120 VAC needs to open up the ATS. Could be as simple as loose connection(s). Could be loose connections have created resistance which has burned wires in there and is dangerous.

Continuing to continue with no diagnosis is taking a risk.

For now my friend is running a heater and a lamp on an extension cord and waiting for me to visit.

Pretty sure it will all make sense when I see it.

[wolfe10]

Someone safe working around 120 VAC needs to open up the ATS. Could be as simple as loose connection(s). Could be loose connections have created resistance which has burned wires in there and is dangerous.

Continuing to continue with no diagnosis is taking a risk.

[hertfordnc]

time2roll wrote:
Nothing wrong with putting an outlet/connector on the generator that matches the main cord. Although you will probably be half way to the cost of a new switch by the time you do it properly.

+1 to unplug and inspect the existing switch before spending money.

For all we know the pedestal supply could be bad. Maybe have the RV park take a quick look before you go out there.

Initially he thought it was the park power. But his problems were intermittent.

It went from no power from the pole- then he got power to half his coach - then he switched to the generator and he had all power everywhere.

So the park moved his site (apparently the maintenance guy can't meter the pole)

This went on for a few weeks with intermittent success.

Finally, when the coach would not take power from the generator and when he called me to discuss it, we started to think it's the transfer switch.

SO i'm thinking at some point the TS was not fully switching both lines? That would explain the partial power, right?


And then it was not switching at all and defaulting to the generator?

And then it failed completely and created an open. ut i think we have a paln to get a new TS and I'l get up there in the next couple weeks to install it.

I love what a thorough discussion this forum has when you ask a question in January 🙂

[Bumpyroad]

larry cad wrote:

Tom/Barb wrote:

AllegroD wrote:
The Automatic Transfer Switches, in an RV, are generally generator priority.

ours isn't, if you are running equipment on the get-set, then plug into 50 amp service the 50 amp service will accept the load, and relieve the get-set.

Thus the name, "AUTOMATIC transfer switch"

🙂

I thought transfer switches were all "automatic"? the other option is just to move the plug to a different outlet mechanically and is not a transfer switch.
bumpy

[larry_cad]

Tom/Barb wrote:

AllegroD wrote:
The Automatic Transfer Switches, in an RV, are generally generator priority.

ours isn't, if you are running equipment on the get-set, then plug into 50 amp service the 50 amp service will accept the load, and relieve the get-set.

Thus the name, "AUTOMATIC transfer switch"

🙂

[Rick_Jay]

Tom/Barb, I believe ours is the same as yours. I know when I plug our rig into shore power, I hear an immediate "clunk" from the contactors in the ATS when I energize the breaker.

[Tom_Barb]

AllegroD wrote:
The Automatic Transfer Switches, in an RV, are generally generator priority.

ours isn't, if you are running equipment on the get-set, then plug into 50 amp service the 50 amp service will accept the load, and relieve the get-set.

[Big_Katuna]

Not necessary. Our first class A didn’t have a transfer switch. Genset recep.

Convenient when the power goes out in a storm and you can start genset from inside without going out.

[tropical36]

camperdave wrote:
What's the point of the transfer switch? When would you ever run the generator while plugged in? just wondering. My rig is wired like you are suggesting, there is a generator outlet I plug the shore cord into when driving, then plug it into the pedestal when at camp.

The only thing, they might be good for, is for scheduling starts to charge the batteries, having it auto start, in case of power loss and with some people leaving their pets for long periods of time in extreme heat conditions.
Also if need be, I can start our genset from next to our bed, in case of power loss during the night and for ac or the heat pumps.
All this is probably never used by most and we never have, with always having the genset on manual operation.