Installing solar panels requires a lot of climbing and hauling. To describe this, you'll use motion verbs like monter (to go up), descendre (to go down), and sortir (to go out).
Verbs of motion use être in the passé composé when describing the subject's own movement. However, when these verbs take a direct object—meaning you are taking or bringing something up, down, or out—they switch their auxiliary to avoir.
Monter (To go up / To take up)
When subjects move themselves, use être and agree the past participle with the subject:
| The workers went up on the scaffolding to see the framework. | Les ouvriers sont montés sur l'échafaudage pour voir la charpente. |
When there is a direct object (like hauling up panels), switch the auxiliary to avoir (and drop the subject agreement):
| Then, they took the photovoltaic panels up on the slope. | Ensuite, ils ont monté les panneaux photovoltaïques sur la pente. |
Descendre (To go down / To take down)
The same applies to descendre. For the subject's own movement, use être:
| He went down to look for the harness and the wiring. | Il est descendu pour chercher le harnais et le câblage. |
For taking an object down, use avoir:
| He took the wiring down for lack of sunlight. | Il a descendu le câblage faute d'ensoleillement. |
Sortir (To go out / To take out)
For sortir, use être when going out:
| He went out on the framework with his harness. | Il est sorti sur la charpente avec son harnais. |
And avoir when taking something out:
| They took out the mounts to tilt the panel. | Elles ont sorti les fixations pour incliner le panneau. |
You can even use both auxiliaries in the same sentence:
| I went up on the slope and I took the wiring down. | Je suis monté sur la pente et j'ai descendu le câblage. |
