---
title: "New Generator Set Installation | Rancho Santa Margarita"
description: "Compartment fabrication, exhaust routing, fuel pickup and transfer switch integration for new RV generator sets. Built in Yorba Linda near Rancho Santa Margarita."
focus_keyword: "new generator set installation rancho santa margarita"
canonical: https://ocrv.me/services/generator-repair/generator-installation/
kind: subService
updated: 2026-07-29
source: OCRV Center
---

# New Generator Set Installation and Compartment Fabrication

> Fitting a set is mostly **compartment fabrication, exhaust routing and chassis weight**, not electrical work. Installations run **$2,500 to $12,000+** across 12 to 45 hours.

## What does installing a new RV generator set involve?

A generator installation means building or adapting a compartment, mounting the set on isolators, routing exhaust safely away from windows and doors, adding a fuel pickup, and integrating with the transfer switch. Rancho Santa Margarita owners have these built in Yorba Linda because the work is fabrication as much as it is wiring.

- Exhaust must terminate well clear of windows, doors and intakes
- Fuel pickup tubes are set so the set cannot empty the chassis tank
- Compartment weight changes axle loading and has to be checked
- The set feeds the coach through a transfer switch, never a plug

### Key facts

| Item | Value |
| --- | --- |
| Price range | $2,500 to $12,000+ (12 to 45 labor hours at $260 per hour) |
| Labor rate | $260 per hour (Mechanical and electrical department) |
| Typical turnaround | 5 to 15 shop days (Fabrication and cure times are scheduled rather than compressed) |
| Written estimate | $150 (Credited in full against an authorized repair) |
| Fuels handled | Gasoline, diesel and LP vapor (Chosen to match what the coach already carries) |

Adding a set to a coach that never had one is a construction project with an electrical component, not the other way around. The generator itself arrives on a pallet and bolts down in an afternoon. What takes the fortnight is building somewhere for it to live, getting exhaust out of the coach safely, and feeding it fuel without compromising the chassis supply.

Replacing a set that has reached the end is usually simpler, but only usually. Compartment dimensions change between model generations, mounting patterns shift, and a modern unit frequently wants different ventilation than the one it is following. We measure before we quote rather than assuming a drop in fit.

## Why owners add a set to a coach that never had one

The usual trigger is load growth. A trailer bought with a single roof air and an absorption refrigerator gets a residential refrigerator during a remodel, then a second air conditioner, then induction cooking, and the electrical plan quietly falls a long way behind the appliance list. Battery and solar can carry a lot of that, but neither will start a compressor at four in the afternoon in August without a very large investment.

The second trigger is commercial. Food trucks, workshops, clinics and command units need power that does not depend on where they parked, and their duty cycle makes a generator the practical answer rather than an optional convenience. Those installations are specified around continuous output rather than around occasional camping use, which changes both the model and the compartment.

- Appliance additions that outgrew the original electrical plan
- A failed original set with no remaining parts support
- Commercial duty cycles that need output regardless of location
- Conversions where the build specification changed after the body was finished

## Choosing a fuel and sizing the set to the loads

Fuel choice usually follows what the coach already carries. A gasoline motorhome takes a gasoline set drawing from the chassis tank through a dedicated pickup. A diesel pusher takes a diesel set. Towables have no engine fuel supply at all, which is why LP vapor sets are common on fifth wheels and trailers where the propane system is already there and sized to support the draw.

Sizing is arithmetic rather than opinion. We add up the loads that must run simultaneously, allow for the surge a compressor demands at start, and choose a rating with genuine headroom above that figure. Undersizing produces a set that nuisance trips and lives at full output, which is hard on it. Oversizing produces the light loading problem that fouls a set from the other direction.

**Matching set fuel to the coach**

| Coach type | Usual fuel | Supply arrangement |
| --- | --- | --- |
| Gasoline motorhome | Gasoline | Dedicated pickup in the chassis tank |
| Diesel pusher | Diesel | Dedicated pickup, returns plumbed separately |
| Fifth wheel or trailer | LP vapor | Tied into the propane system with regulator capacity checked |
| Commercial conversion | Diesel or LP | Chosen around duty cycle and refuelling logistics |

## The compartment is most of the job

A generator compartment has to do four things at once. It carries a heavy mass that vibrates continuously, so the structure beneath it must be rated for that rather than borrowed from a storage floor. It seals against the living space so exhaust and fumes cannot migrate inward. It breathes enough to keep the set within its temperature limits in an Orange County August. And it opens well enough that the set can actually be serviced afterward.

Getting those four to coexist in an existing coach is where the hours go. Frame members are where they are, tanks are where they are, and the openings on that side of the body were placed by somebody who never imagined a generator would live there. On larger installations a slide out tray solves the service access problem elegantly, and it adds its own structural demands in exchange.

> **warning:** Combustion air must come from outside the coach, never from the living space. A compartment that is not properly sealed and separately ventilated turns a generator into an appliance that competes with the people inside for oxygen.

## Exhaust routing and carbon monoxide

This is the part of the project where mistakes hurt people rather than equipment. Exhaust has to leave the coach at a point well clear of every window, door, roof vent and fresh air intake, and it has to keep doing so when the coach is parked at an angle or when a breeze pushes fumes back along the body. Terminating at the nearest convenient hole in the skin is not an installation, it is a hazard.

Routing matters as much as termination. Tubing is kept away from fuel lines and wiring, supported so it cannot resonate against the frame, and isolated at the connection so engine movement is not transmitted into the body. We also verify carbon monoxide detection inside the coach as part of commissioning, because a detector that has aged out is not protection.

1. Terminate well clear of every window, door, vent and intake
2. Route away from fuel lines and electrical runs
3. Support the tubing so vibration cannot resonate through the body
4. Confirm working carbon monoxide detection before handover

## Tying a new set into the coach electrical system

The set never plugs into the coach. It feeds an automatic transfer switch installed ahead of the load center, and that switch decides which source the panel sees. Doing it any other way puts the responsibility for source selection on whoever is holding the cord, and it permits configurations that should not be physically possible.

Beyond the switch, the feed is sized and protected to the set output, remote start goes to a panel the owner can actually reach, and any energy management or surge equipment already fitted is reviewed so it sits in the right position in the chain. On coaches where an inverter charger is already installed, the interaction between it and the new source is checked during commissioning rather than discovered on the road.

## Where the twelve to forty five hours go

Installations bill at $260 per hour from the mechanical and electrical department, and the spread across this page is a fabrication spread rather than an electrical one. Dropping a replacement set into a compartment that is already sound, already ventilated and already wired occupies the bottom of the range. Building a compartment into a fifth wheel that never had one, with a new fuel path and a transfer switch, occupies the top.

The set itself, isolators, exhaust components and the transfer switch carry standard parts markup, with tax on parts and materials. Fluid and LP handling brings the $45 hazmat charge. A written repair estimate is $150 and credits in full. Projects at this scale pass both deposit thresholds, so a deposit applies at authorization and a further amount when parts arrive.

> **price:** We quote the compartment separately from the set on every installation. Owners are entitled to see how much of the number is hardware and how much is building somewhere for that hardware to live.

## Weight, axle load and what the chassis allows

A generator plus its compartment, exhaust and fuel provision is a meaningful mass added at a specific point on a chassis that already has a rating. On a large motorhome the margin usually exists. On a lighter travel trailer, adding a set on one side without accounting for it can push an axle past its limit or introduce a lateral imbalance that shows up as tire wear and handling complaints.

So the weight conversation happens before the model is chosen rather than after the compartment is built. We check axle ratings, look at what is already loaded on that side, and where necessary steer an owner toward a lighter set or a different location. It is a less exciting conversation than output ratings and it prevents a genuinely expensive mistake.

## Cost

$2,500 to $12,000+, based on 12 to 45 labor hours at $260 per hour.

Written repair estimate is $150, credited in full against an authorized repair. All work is performed in shop.

## Questions and answers

### Can a generator be added to a travel trailer that never had one?

Yes, and it is the largest version of this job. A compartment has to be built with structure to carry the set, sealing against the interior, ventilation and service access, plus an LP or fuel supply and a transfer switch. Weight and axle capacity get checked before a model is chosen.

### Should a fifth wheel run an LP generator or a gasoline one?

LP vapor is the common answer because a towable carries no engine fuel supply, and the propane system is already aboard. What matters is regulator and tank capacity, since a set adds a substantial draw. We verify that the existing propane system can support the load before specifying one.

### Why does a generator installation take two weeks when the unit bolts down quickly?

Because the set is the small part. Building a compartment that carries the mass, seals from the living space, breathes enough to stay cool and still opens for service is the bulk of the labor, and exhaust routing has to be done carefully rather than quickly.

### How far does generator exhaust need to be from a window?

Well clear of every window, door, roof vent and fresh air intake, with the coach parked at an angle taken into account. This is the one item on an installation where an error harms people rather than equipment, so we route and terminate conservatively and verify detection before handover.

### Will an onboard generator drain my fuel tank completely?

Not when the pickup is installed correctly. A dedicated tube stops well above the chassis engine pickup so the set shuts down while the coach can still be driven. Aftermarket installations that plumb to the bottom of the tank are the reason this question gets asked.

### How much generator capacity should I specify above my actual load?

Enough to cover compressor surge with genuine headroom, but not so much that the set spends its life lightly loaded. Undersizing causes nuisance tripping and constant full output running. Oversizing causes carbon fouling. We total the simultaneous loads and size deliberately between those two failure modes.

---

Source: [OCRV Center](https://ocrv.me/services/generator-repair/generator-installation/). Last verified 2026-07-29.