> For the complete documentation index, see [llms.txt](https://docs.pulse.domains/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.pulse.domains/deep-dives/name-wrapper/fuses.md).

# Fuses

### **What Are Fuses in PNS?**

Fuses in PNS are like digital settings for your .pls domain names. They allow you to grant or revoke certain permissions or features. Once a fuse is "burned" (activated), it can't be reversed until the domain's expiry date.

### **Types of Fuses in PNS**

#### **Parent-Controlled Fuses**

Set by the owner of the main .pls domain, these fuses determine the capabilities and restrictions of subdomains.

* **PARENT\_CANNOT\_CONTROL**: Allows the main domain owner to grant independence to a subdomain. Once activated, the main domain can no longer modify or delete the subdomain.
* **IS\_DOT\_ETH**: This is an internal setting for when a .pls second-level domain is wrapped. It's not user-controlled.
* **CAN\_EXTEND\_EXPIRY**: Enables the subdomain owner to extend their domain's expiry date independently.
* **Custom Fuses**: There are 13 additional parent-controlled fuses that can be customized for various purposes.

<figure><img src="/files/huuiQjBjNwkSnlCoscA6" alt=""><figcaption><p><strong>Parent-Controlled Fuses</strong></p></figcaption></figure>

#### **Owner-Controlled Fuses**

These can be set by either the subdomain owner or the main domain owner, acting as permissions that can be revoked.

* **CANNOT\_UNWRAP**: Locks the domain, preventing it from being converted back to a non-NFT state. This is a prerequisite for burning other owner-controlled fuses.
* **CANNOT\_BURN\_FUSES**: Freezes the current state of fuses, preventing any further changes.
* **CANNOT\_TRANSFER**: Stops the domain from being transferred to another owner.
* **CANNOT\_SET\_RESOLVER**: Disables updates to the resolver contract for the domain.
* **CANNOT\_SET\_TTL**: Prevents changes to the domain's Time To Live (TTL) setting.
* **CANNOT\_CREATE\_SUBDOMAIN**: Prohibits the creation of new subdomains.
* **CANNOT\_APPROVE**: Restricts updates to the approved "subname renewal manager" for the domain.
* **Custom Fuses**: There are 9 more owner-controlled fuses available for custom use.

<figure><img src="/files/TLq0oJhu8ugw3KMm5O76" alt=""><figcaption><p>Owner-Controlled Fuses</p></figcaption></figure>

### **Understanding Emancipated and Locked States**

* **Emancipated State**: A subdomain enters this state when it gains independence, typically after the PARENT\_CANNOT\_CONTROL fuse is burned. In this state, the main domain can't alter the subdomain until it expires.
* **Locked State**: A domain in this state cannot be unwrapped, ensuring the stability and security of its settings and subdomains.

### **Hierarchical Nature of Fuses**

* Fuses operate in a hierarchical manner. For example, to burn owner-controlled fuses, the domain must be in a locked state.
* To lock a domain (burn the CANNOT\_UNWRAP fuse), the parent domain must have burned the PARENT\_CANNOT\_CONTROL fuse.

### **DNS Domains and Fuses**

* Currently, the fuse system is mainly for .pls domains. DNS domain owners can technically use fuses, but their control is ultimately governed by the DNS network and not fully within PNS.

### **Key Takeaways**

* Fuses offer sophisticated management of your .pls domain names, allowing for a wide range of permissions and features.
* They provide a means to customize your .pls domains, enhancing their functionality and security.
* Understanding the hierarchical nature and the specific functions of each fuse can greatly enhance your experience with PNS.